Patent Publication Number: US-9839924-B2

Title: Foamer dispenser

Description:
TECHNICAL FIELD 
     The present invention relates to a foamer dispenser. 
     Priority is claimed on Japanese Patent Application No. 2013-148943, filed on Jul. 17, 2013, Japanese Patent Application No. 2013-148944, filed on Jul. 17, 2013, Japanese Patent Application No. 2013-148945, filed on Jul. 17, 2013, and Japanese Patent Application No. 2013-148946, filed on Jul. 17, 2013, the contents of which are incorporated herein by reference. 
     BACKGROUND ART 
     Conventionally, a foamer dispenser described in, for example, Patent Document 1 below is known. This foamer dispenser includes: an attachment cap that is attached to a mouth portion of a container main unit in which a content substance is to be contained; a discharge device with a stem that is erected through the attachment cap so as to be movable downwardly while being biased upwardly; and a depressing head which is attached to the stem and in which a nozzle hole is formed. 
     The discharge device includes: a piston for liquid that is linked to the stem; a cylinder for liquid in which the piston for liquid is contained so as to be freely slidable in the up-down direction; a piston for air that is linked to the stem; and a cylinder for air in which the piston for air is contained so as to be freely slidable in the up-down direction. The discharge device further includes: an air-liquid mixing chamber that mixes liquid from the cylinder for liquid with air from the cylinder for air; and a foaming member that is disposed between the air-liquid mixing chamber and the nozzle hole and foams an air-liquid mixture from the air-liquid mixing chamber. 
     The attachment cap includes: an annular ceiling wall portion that is arranged above the mouth portion of the container main unit; and a guide cylindrical portion that is erected on an inner circumferential edge of the ceiling wall portion. The depressing head includes: a top wall portion that is arranged above the stem; an attachment cylindrical portion that extends downwardly from the top wall portion and is attached to the stem; and an exterior cylindrical portion that extends downwardly from the top wall portion and surrounds the attachment cylindrical portion and the guide cylindrical portion from the outer side in the radial direction. The inside of the exterior cylindrical portion is in communication with the inside of the cylinder for air through the inside of the guide cylindrical portion. 
     In the foamer dispenser with this structure, when the depressing head is depressed to move the stem downwardly against the biasing force, the discharge device is activated to cause a foam-like content substance to be discharged from the nozzle hole. After that, when the depressing of the depressing head is released to allow the biasing force to move back the depressing head together with the stem upwardly, the inside of the cylinder for air has a negative pressure. Then, the air is sucked into the exterior cylindrical portion from the outside of the foamer dispenser through a gap between the inner circumferential surface of the exterior cylindrical portion and the outer circumferential surface of the guide cylindrical portion (hereinafter, referred to as “cylinder-cylinder gap”) and is subsequently drawn into the cylinder for air through the inside of the guide cylindrical portion. 
     CITATION LIST 
     Patent Documents 
     Patent Document 1: Japanese Unexamined Patent Application, First Publication No. 2009-202122 
     SUMMARY OF INVENTION 
     Technical Problem 
     However, in the conventional foamer dispenser as described above, if foreign matter such as water is attached to the external surface of the attachment cap, the foreign matter together with air may be sucked into the exterior cylindrical portion through the cylinder-cylinder gap when the depressing head is moved back upwardly. As a result, the foreign matter may intrude into the cylinder for air. 
     Furthermore, in the conventional foamer dispenser as described above, for example from the viewpoint of molding, there are cases where as for the depressing head, a connected body of the top wall portion and the attachment cylindrical portion (hereinafter, referred to as head main unit) and the exterior cylindrical portion are preferably formed as separate entities. 
     In this case, it is necessary to attach the exterior cylindrical portion tightly to the head main unit, to thereby prevent the exterior cylindrical portion from being removed due to a shock from being dropped or from shaking. 
     Furthermore, in the conventional foamer dispenser as described above, there are cases where some users depress the depressing head in an oblique direction. Therefore, it is desired that this oblique depressing be restricted. 
     In the conventional foamer dispenser as described above, for example from the viewpoint of molding, there are cases where as for the depressing head, the head main unit and the exterior cylindrical portion are preferably formed as separate entities. In this case, if the depressing head is depressed in an oblique direction, the positional relationship in the radial direction between the exterior cylindrical portion and the head main unit is likely to be unstable. 
     Furthermore, in the conventional foamer dispenser as described above, there are cases where a user depresses the depressing head while, for example, holding a nozzle cylindrical portion in which a discharge hole opens. In this case, there is a possibility that, as a result of being depressed obliquely with respect to the attachment cap, the discharge device is not allowed to be depressed straightly toward the downward direction. Therefore, it is desired that the oblique depressing of the discharge device be restricted. 
     The present invention has been achieved in view of the aforementioned circumstances, and has an object to provide a foamer dispenser that makes it possible to inhibit foreign matter such as water from intruding into a cylinder for air. 
     Furthermore, the present invention has been achieved in view of the aforementioned circumstances, and has an object to provide a foamer dispenser in which it is possible to attach an exterior cylindrical portion tightly to a head main unit. 
     Furthermore, the present invention has been achieved in view of the aforementioned circumstances, and has an object to provide a foamer dispenser in which it is possible to restrict an oblique depressing of a depressing head, to thereby stabilize the positional relationship in the radial direction between the exterior cylindrical portion and the head main unit. 
     Furthermore, the present invention has been achieved in view of these circumstances, and has an object to provide a foamer dispenser in which, when the depressing head is depressed, it is possible to inhibit a discharge device from being depressed obliquely with respect to an attachment cap and from shaking. 
     Solution to Problem 
     To solve the above problems, the present invention proposes the following. 
     A foamer dispenser according to a first aspect of the present invention includes: an attachment cap that is attached to a mouth portion of a container main unit in which a content substance is contained; a discharge device having a stem that is erected through the attachment cap so as to be movable downwardly while being biased upwardly; and a depressing head which is attached to the stem and in which a nozzle hole is formed, in which the discharge device includes: a piston for liquid that is linked to the stem; a cylinder for liquid in which the piston for liquid is contained so as to be freely slidable in an up-down direction; a piston for air that is linked to the stem; a cylinder for air in which the piston for air is contained so as to be freely slidable in the up-down direction; an air-liquid mixing chamber that mixes liquid from the cylinder for liquid with air from the cylinder for air; and a foaming member that is disposed between the air-liquid mixing chamber and the nozzle hole and foams an air-liquid mixture from the air-liquid mixing chamber, in which the attachment cap includes: an annular ceiling wall portion that is arranged above the mouth portion; and a guide cylindrical portion that is erected on the ceiling wall portion, in which the depressing head includes: a head main unit having a top wall portion arranged above the stem, and an attachment cylindrical portion that extends downwardly from the top wall portion and is attached to the stem; and an exterior cylindrical portion that is provided beneath the top wall portion and surrounds the attachment cylindrical portion and the guide cylindrical portion from an outer side in a radial direction, in which an inside of the exterior cylindrical portion is communicable with an inside of the cylinder for air through an inside of the guide cylindrical portion, in which the head main unit and the exterior cylindrical portion are formed as separate entities and are fitted to each other, and in which, in an upper end portion of the exterior cylindrical portion, an intake hole is formed that penetrates through the exterior cylindrical portion in the radial direction and opens toward an upward direction. 
     According to this invention, the intake hole is formed in the upper end portion of the exterior cylindrical portion. Therefore, when the depressing of the depressing head is released to cause the inside of the cylinder for air to have a negative pressure, it is possible to suck outside air into the exterior cylindrical portion through the intake hole. Consequently, it is possible to inhibit the outside air from being sucked into the exterior cylindrical portion through a gap between an inner circumferential surface of the exterior cylindrical portion and an outer circumferential surface of the guide cylindrical portion (hereinafter, referred to as “cylinder-cylinder gap”), and hence, to inhibit foreign matter together with the outside air from being sucked into the exterior cylindrical portion through the cylinder-cylinder gap. As a result, it is possible to inhibit the intrusion of foreign matter into the cylinder for air. 
     Furthermore, the intake hole is formed in the upper end portion of the exterior cylindrical portion. Therefore, it is possible to maintain a low influence that the intake hole has on the appearance of the depressing head. 
     Furthermore, the intake hole opens toward the upward direction. Therefore, for example, when the exterior cylindrical portion is molded with a mold, it is possible to remove the mold with ease, and hence, to make it easy to form the foamer dispenser in a simplified manner. 
     In the foamer dispenser according to the first aspect of the present invention, in an opening circumferential edge of the intake hole in an outer circumferential surface of the exterior cylindrical portion, a receding section may be formed that recedes inwardly in the radial direction and is in communication with the intake hole. 
     In this case, the receding sections are formed in the opening circumferential edges of the intake holes in the outer circumferential surface of the exterior cylindrical portion. This makes it difficult for foreign matter such as water to intrude. Furthermore, it is possible to introduce outside air into the intake holes through the receding sections, and hence, to effectively suck the outside air into the exterior cylindrical portion through the intake holes. 
     In the foamer dispenser according to the first aspect of the present invention, the head main unit may be provided with a covering wall portion that extends downwardly from the top wall portion and covers the intake hole from an outer side in the radial direction. 
     In this case, the head main unit includes the covering wall portion. Therefore, it is possible to inhibit the intake holes from being exposed to the outside, and hence, to maintain the appearance of the foamer dispenser favorable. 
     In the foamer dispenser according to the first aspect of the present invention, the top wall portion may be provided with a pair of lock portions that protrude downwardly, are spaced in a circumferential direction, and are locked between parts of an inner circumferential edge of the intake hole that face inwardly in the circumferential direction. 
     In this case, the top wall portion is provided with the pair of lock portions. Therefore, when the head main unit and the exterior cylindrical portion are to rotate relatively to each other in the circumferential direction, the lock portions are locked in the inner circumferential edges of the intake holes, to thereby make it possible to restrict the rotation. Furthermore, when the exterior cylindrical portion is to be deformed so that the intake holes are narrowed in the circumferential direction, the lock portions are locked in the inner circumferential edges of the intake holes. Thereby, it is possible to restrict the deformation. 
     Furthermore, the pair of lock portions is spaced in the circumferential direction. Therefore, while the rotation and deformation as described above are being restricted, it is possible to securely bring the inside and outside of the exterior cylindrical portion into communication with each other through a part of the intake hole that is located between the pair of lock portions, and hence, to securely suck the outside air into the exterior cylindrical portion through the intake hole. 
     If the top wall portion is provided with the fitting cylindrical portion that protrudes downwardly and that is fitted onto the attachment cylindrical portion, and the lock portions connect between the attachment cylindrical portion and the fitting cylindrical portion, then when the lock portions are locked in the inner circumferential edges of the intake holes, it is possible to support both ends of the lock portions in the radial direction by means of the attachment cylindrical portion and the fitting cylindrical portion. Therefore, it is possible to effectively restrict the aforementioned rotation and deformation. 
     In the foamer dispenser according to the first aspect of the present invention, the top wall portion may be provided with a plurality of support plate portions that protrude downwardly, extend in the radial direction, and are arranged in the circumferential direction; inner ends of the support plate portions in the radial direction are connected to the attachment cylindrical portion; and outer ends of the support plate portions in the radial direction support the exterior cylindrical portion from an inner side in the radial direction. 
     In this case, the plurality of support plate portions are arranged in the top wall portion, and moreover, the ends of the support plate portions on the inner side in the radial direction are connected to the attachment cylindrical portion while the ends of the support plate portions on the outer side in the radial direction support the exterior cylindrical portion from the inner side in the radial direction. Therefore, for example, when the exterior cylindrical portion is about to shake in the radial direction with respect to the head main unit, it is possible to cause the top wall portion and the attachment cylindrical portion to support the exterior cylindrical portion via the support plate portions. As a result, it is possible to attach the exterior cylindrical portion tightly to the head main unit. Therefore, for example, it is possible to inhibit shaking between the exterior cylindrical portion and the head main unit. 
     In the foamer dispenser according to the first aspect of the present invention, the top wall portion may be provided with a fitting cylindrical portion that protrudes downwardly and is fitted onto the attachment cylindrical portion. 
     In this case, the top wall portion is provided with the fitting cylindrical portion. This makes it possible to sandwich the exterior cylindrical portion between the support plate portions and the fitting cylindrical portion in the radial direction. Therefore, it is possible to attach the exterior cylindrical portion further tightly to the head main unit. 
     In the foamer dispenser according to the first aspect of the present invention, the lock portion may be formed in a plate shape that extends in the radial direction and an end thereof in the radial direction is connected to the attachment cylindrical portion; and an in-cylinder portion of the lock portion that is located on a more inner side than the exterior cylindrical portion in the radial direction may protrude further downwardly than a part of the lock portion that is located in the intake hole and may support the exterior cylindrical portion from the inner side in the radial direction. 
     In this case, the in-cylinder portions of the lock portions support the exterior cylindrical portion from the inner side in the radial direction. This makes it possible to support the exterior cylindrical portion from the inner side in the radial direction not only by the support plate portions but also by the in-cylinder portions of the lock portions. Therefore, it is possible to attach the exterior cylindrical portion further tightly to the head main unit. 
     In the foamer dispenser according to the first aspect of the present invention, an inner circumferential surface of the exterior cylindrical portion may be protrudingly provided with guide ribs that extend in the up-down direction. 
     In this case, the guide ribs are protrudingly provided on the inner circumferential surface of the exterior cylindrical portion. Therefore, for example, when the depressing head is obliquely depressed, the guide cylindrical portion is made slidable on the guide ribs, in the up-down direction, and hence, it is possible to restrict the displacement of the exterior cylindrical portion in the radial direction by means of the guide cylindrical portion. As a result, it is possible to stabilize the position of the exterior cylindrical portion in the radial direction. Consequently, it is possible to stabilize the positional relationship between the exterior cylindrical portion and the head main unit in the radial direction. 
     In the foamer dispenser according to the first aspect of the present invention, the guide ribs may be arranged in sections of the exterior cylindrical portion that are opposite to each other across the guide cylindrical portion. 
     In this case, the guide ribs are arranged in the sections of the exterior cylindrical portion that are opposite to each other in the radial direction across the guide cylindrical portion. Therefore, when the depressing head is obliquely depressed, the guide ribs are made capable of slidably contacting the guide cylindrical portion from both outer sides in the radial direction. Consequently, it is possible to further stabilize the position of the exterior cylindrical portion in the radial direction. 
     In the foamer dispenser according to the first aspect of the present invention, the head main unit may include a nozzle cylindrical portion which extends outwardly in the radial direction from the attachment cylindrical portion to protrude more outwards in the radial direction than the exterior cylindrical portion and a protrusion end of which is provided with the nozzle hole, and the guide rib may include: a first guide rib that is arranged in a part of the exterior cylindrical portion that is positionally equivalent to the nozzle cylindrical portion in the circumferential direction; and a second guide rib that is arranged in a part opposite to the first guide rib in the radial direction across the guide cylindrical portion. 
     The head main unit includes the nozzle cylindrical portion. For example, in the case where the depressing head is depressed with the nozzle cylindrical portion being held, the depressing head is likely to be depressed obliquely. Consequently, the positional relationship between the exterior cylindrical portion and the head main unit is likely to be unstable in the forward-rearward direction, which is a direction in which the nozzle cylindrical portion extends. 
     Here, the first guide rib and the second guide rib are arranged in the sections of the exterior cylindrical portion that are located on both sides in the forward-rearward direction. Therefore, when the depressing head is obliquely depressed, it is possible to stabilize the position of the exterior cylindrical portion in the forward-rearward direction by means of the first guide rib and the second guide rib. Therefore, it is possible to securely stabilize the positional relationship between the exterior cylindrical portion and the head main unit in the forward-rearward direction. 
     A foamer dispenser according to a second aspect of the present invention includes: an attachment cap that is attached to a mouth portion of a container main unit in which a content substance is contained; and a discharge device that has a stem erected through the attachment cap so as to be movable downwardly while being biased upwardly and that has a depressing head which is attached to the stem and in which a discharge hole is formed, in which the discharge device includes: a piston for liquid that moves in an up-down direction in conjunction with the stem; a cylinder for liquid in which the piston for liquid is disposed so as to be slidable in the up-down direction; a piston for air that moves in the up-down direction in conjunction with the stem; a cylinder for air in which the piston for air is disposed so as to be slidable in the up-down direction; an air-liquid mixing chamber that mixes a liquid content transferred from the cylinder for liquid with air transferred from the cylinder for air; and a foaming member that is disposed between the air-liquid mixing chamber and the discharge hole and foams an air-liquid mixture having been mixed in the air-liquid mixing chamber, in which the attachment cap includes a guide portion through which the discharge device is inserted in the up-down direction, and in which either one of an outer circumferential surface of an insertion section of the discharge device that is inserted through the guide portion and an inner circumferential surface of the guide portion is provided with guide ribs that are slidable in the up-down direction with respect to the other. 
     According to the foamer dispenser of the second aspect of the present invention, either one of the outer circumferential surface of the insertion section of the discharge device that is inserted through the guide portion of the attachment cap and the inner circumferential surface of the guide portion of the attachment cap is provided with the guide ribs that are slidable in the up-down direction with respect to the other. Therefore, even if, when the depressing head is depressed, the discharge device does not move straightly toward the downward direction but is to move in a direction that crosses the up-down direction, the guide ribs move up and down while sliding on the circumferential surface of the other. As a result, it is possible to inhibit the discharge device from being depressed obliquely forwardly or rearwardly instead of straightly downwardly and from shaking with respect to the attachment cap. 
     From above, when the depressing head is depressed, it is possible to inhibit the oblique depressing or shaking (hereinafter, sometimes referred to shortly as shaking or the like) of the discharge device with respect to the attachment cap, and hence, to stabilize the positional relationship between the discharge device and the attachment cap in the radial direction. This stabilizes the operation of depressing. Therefore, operability of the foamer dispenser is enhanced. 
     In the foamer dispenser according to the second aspect of the present invention, the piston for air may include an inner slide cylinder, the stem may be inserted into the inner slide cylinder so as to be movable in the up-down direction, the guide portion may include: an annular ceiling wall portion which is arranged above the mouth portion and through which the stem is inserted; and a guide cylindrical portion that is erected on an inner circumferential edge of the ceiling wall portion, and the guide ribs may include third guide ribs that are provided on either one of the inner slide cylinder and the ceiling wall portion so as to be slidable with respect to the other. 
     In this case, as guide ribs, the third guide ribs, which are slidable with respect to the other in the up-down direction, are provided with either one of the inner slide cylinder of the piston for air and the ceiling wall portion of the attachment cap. Therefore, shaking or the like when the piston for air of the discharge device is moved up and down with respect to the ceiling wall portion of the attachment cap is inhibited. Consequently, the aforementioned effect is further enhanced. 
     In the foamer dispenser according to the second aspect of the present invention, the ceiling wall portion may be provided with an insertion cylinder into which the inner slide cylinder is inserted. 
     In this case, it is possible to obtain a length along the up-down direction that is sufficiently long to allow the insertion cylinder of the ceiling wall portion and the inner slide cylinder of the piston for air to contact each other. Consequently, the aforementioned effect of inhibiting shaking or the like of the discharge device is further enhanced. 
     In the foamer dispenser according to the second aspect of the present invention, the third guide ribs may be provided on the inner slide cylinder. 
     Through the inner slide cylinder of the piston for air, the stem is inserted. The inner slide cylinder and the stem are inserted into the ceiling wall portion of the attachment cap. In the case of this structure, it is possible to obtain a more sufficient length of the third guide rib along the up-down direction. Consequently, the aforementioned effect of inhibiting shaking or the like of the discharge device is further enhanced. 
     In the foamer dispenser according to the second aspect of the present invention, the depressing head may include: a top wall portion that is arranged above the stem; and an attachment cylindrical portion that protrudes downwardly from the top wall portion and is attached to the stem, and the guide ribs may include fourth guide ribs that are provided on either one of the attachment cylindrical portion and the guide cylindrical portion so as to be slidable with respect to the other. 
     In this case, as guide ribs, the fourth guide ribs, which are slidable in the up-down direction with respect to the other, are provided with either one of the attachment cylindrical portion of the depressing head and the guide cylindrical portion of the attachment cap. Therefore, shaking or the like when the depressing head of the discharge device is moved in the up-down direction with respect to the guide cylindrical portion of the attachment cap is inhibited. Consequently, the aforementioned effect is further enhanced. 
     Furthermore, in this case, the third guide ribs and the fourth guide ribs are allowed to be located in different sections along the up-down direction (allowed to be spaced in the up-down direction). Therefore, it is possible to inhibit the aforementioned shaking or the like of the discharge device especially remarkably. 
     Advantageous Effects of Invention 
     According to the foamer dispenser of the present invention, it is possible to inhibit foreign matter such as water from intruding into the cylinder for air. 
     Furthermore, according to the foamer dispenser of the present invention, with the exterior cylindrical portion being attached tightly to the head main unit, it is possible to prevent the exterior cylindrical portion from being removed due to shock from being dropped down and from shaking. 
     Furthermore, according to the foamer dispenser of the present invention, it is possible to restrict the oblique depressing of the depressing head, to thereby stabilize the positional relationship in the radial direction between the exterior cylindrical portion and the head main unit. 
     Furthermore, according to the foamer dispenser of the present invention, when the depressing head is depressed, it is possible to inhibit the discharge device from being depressed obliquely with respect to the attachment cap and from shaking. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG 1  is a partial longitudinal cross-sectional view of a foamer dispenser according to a first embodiment of the present invention. 
         FIG. 2  is a longitudinal cross-sectional view of the main part of the foamer dispenser shown in  FIG. 1 . 
         FIG. 3  is a partial lateral cross-sectional view of a depressing head constituting the foamer dispenser shown in  FIG. 1 . 
         FIG. 4  is a cross-sectional view of  FIG. 3 , taken along and seen in the direction of the A-A arrow. 
         FIG. 5  is a planar view of an exterior cylindrical portion constituting the depressing head shown in  FIG. 3 . 
         FIG. 6  is a view of a front side of the exterior cylindrical portion shown in  FIG. 5 . It is a half cross-sectional view of  FIG. 5  in which a half side in the left-right direction is shown in a longitudinal cross-sectional view. 
         FIG. 7  is a side view of the exterior cylindrical portion shown in  FIG. 5 . 
         FIG. 8  is a longitudinal cross-sectional view of a discharge container including a foamer dispenser according to a second embodiment of the present invention. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     (First Embodiment) 
     Hereunder is a description of a foamer dispenser  10  according to a first embodiment of the present invention, with reference to  FIG. 1  to  FIG. 7 . 
     The foamer dispenser  10  transforms the content substance (content liquid) thereof into a bubble form and discharges it. As the content substance, for example a skin wash fluid (body-wash) may be listed. A table of components of an exemplary content substance is shown in Table 1 below. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 Component 
                 Mass % 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                   
                 Sodium lauriminopropionate 
                 3 
               
               
                   
                 Lauramidopropyl betaine 
                 20 
               
               
                   
                 N-sodium methyl cocoyl taurate 
                 2 
               
               
                   
                 Polyoxyethylene(2)alkyl(12-14)sulfosuccinate 
                 10 
               
               
                   
                 disodium 
               
               
                   
                 Sorbitol 
                 3 
               
               
                   
                 Glycerin 
                 3 
               
               
                   
                 Propylene glycol 
                 20 
               
               
                   
                 Sodium benzoate 
                 0.9 
               
               
                   
                 Citric acid 
                 0.7 
               
               
                   
                 Honey 
                 0.1 
               
               
                   
                 DL-sodium pyrrolidone carboxylate solution 
                 0.1 
               
               
                   
                 Dye 
                 0.01 
               
               
                   
                 Purified water 
                 Balance 
               
               
                   
                   
               
            
           
         
       
     
     As shown in  FIG. 1  and  FIG. 2 , the foamer dispenser  10  includes: an attachment cap  11  that is attached to a mouth portion  1   a  of a container main unit  1  in which a content substance is contained; a discharge device  13  with a stem  12  that is erected through the attachment cap  11  so as to be slidable downwardly while being biased upwardly; and a depressing head  15  which is attached to the stem  12  and in which a nozzle hole  14  is formed. 
     The attachment cap  11  is formed in a cylindrical shape opening at the top and bottom thereof. The depressing head  15  is formed in a cylindrical shape with a top. The central axis lines of the attachment cap  11 , the stem  12 , and the depressing head  15  are located on a common axis. Hereinafter, the common axis is referred to as axis line O. A direction along the axis line O is referred to as up-down direction. A side on the depressing head  15  along the up-down direction is referred to as upper side while a side opposite thereto is referred to as lower side. A direction orthogonal to the axis line O is referred to as radial direction. A direction about the axis line O is referred to as circumferential direction. 
     The attachment cap  11  includes: an annular ceiling wall portion  16  arranged above the mouth portion  1   a  of the container main unit  1 ; a guide cylindrical portion  17  that is erected on an inner circumferential edge of the ceiling wall portion  16 ; and an attachment circumferential wall portion  18  which extends downwardly from an outer circumferential edge of the ceiling wall portion  16  and which is attached to the mouth portion la. Note that the mouth portion la and the attachment circumferential wall portion  18  are fitted to each other by, for example, screwing, undercut, or the like. 
     On an upper end portion of the guide cylindrical portion  17 , an inner guide protrusion  17   a  is provided that protrudes outwardly in the radial direction. The inner guide protrusion  17   a  is formed in an annular shape. To the part of the guide cylindrical portion  17  that is located on the side lower than the inner guide protrusion  17   a , a restricting member  19  is freely detachably attached that has a C shape when seen in a planar view and restricts the depressing of the depressing head  15 . 
     The stem  12  is inserted through the attachment cap  11 . The stem  12  includes: a lower stem  20 : and an upper stem  21 . 
     An upper end portion of the lower stem  20  is arranged inside the guide cylindrical portion  17 . On an inner circumferential surface of the upper end portion of the lower stem  20 , an annular valve seat  22  is provided that protrudes inwardly in the radial direction. To the valve seat  22 , a liquid discharge valve  23  with a spherical shape is seatably and detachably provided. 
     Inside the upper end portion of the lower stem  20 , a presser member  24  is provided that is formed via a plurality of support pillars extending in the up-down direction. The support pillars are arranged inside the upper end portion of the lower stem  20  so as to be spaced from each other in the circumferential direction. Lower end portions of the support pillars are located on the valve seat  22 . Between the adjacent support pillars, a circulation hole is provided. 
     A lower end portion of the upper stem  21  is fitted onto the upper end portion of the lower stem  20 . The upper stem  21  is inserted into the guide cylindrical portion  17  of the attachment cap  11  so as to be freely movable in the up-down direction. In an intermediate part of the upper stem  21  that is located between the lower end portion and the upper end portion, a reduced-diameter part  21   a  is formed. In an inner circumferential surface of the lower end portion of the upper stem  21 , a plurality of longitudinal grooves  21   b  are formed that extend in the up-down direction. An upper end portion of the longitudinal groove  21   b  opens in an inner side in the radial direction while a lower end portion of the longitudinal groove  21   b  opens in a downward direction. 
     The discharge device  13  further includes: a piston for liquid  25  that is linked to the stem  12 ; a cylinder for liquid  26  in which the piston for liquid  25  is contained so as to be freely slidable in the up-down direction; a piston for air  27  that is linked to the stem  12 ; a cylinder for air  28  in which the piston for air  27  is contained so as to be freely slidable in the up-down direction; an air-liquid mixing chamber  29  that mixes liquid from the cylinder for liquid  26  with air from the cylinder for air  28 ; and a foaming member  30  that is disposed between the air-liquid mixing chamber  29  and the nozzle hole  14  and foams the air-liquid mixture from the air-liquid mixing chamber  29 . 
     The cylinder for air  28  is formed in a cylindrical shape with a bottom. The cylinder for liquid  26  is formed in a cylindrical shape. The cylinder for air  28  and the cylinder for liquid  26  are disposed coaxially with the axis line O. An upper opening section of the cylinder for air  28  is sealed via packing that is provided between an inner surface of the attachment cap  11  and an upper surface of the mouth portion  1   a . The cylinder for liquid  26  extends downwardly from a bottom portion of the cylinder for air  28 . The cylinder for liquid  26  and the cylinder for air  28  are formed integrally. The cylinder for liquid  26  is formed so as to have a diameter smaller than that of the cylinder for air  28 . 
     The piston for air  27  includes: an outer slide cylinder  31  that is fitted into the cylinder for air  28  so as to be freely slidable in the up-down direction in an airtight state; an inner slide cylinder  32  which is arranged on the inner side of the outer slide cylinder  31  and into which the stem  12  is inserted so as to be freely slidable in the up-down direction; a connector plate  33  that connects between an inner circumferential surface of the outer slide cylinder  31  and an outer circumferential surface of the inner slide cylinder  32 ; an air hole  34  that extends through the connector plate  33  in the up-down direction; and a valve body  35  that opens and closes the air hole  34 . 
     Into the inner slide cylinder  32 , the lower stem  20  is inserted. An upper end portion of the inner slide cylinder  32  is fitted into the lower end portion of the upper stem  21  so as to be freely slidable on the inner circumferential surface of the upper stem  21  in the up-down direction. 
     Between an upper edge of the inner slide cylinder  32  and an inner surface of the upper stem  21 , a communication gap S is provided, which is a gap in the up-down direction. In the communication gap S, lower end portions of the longitudinal grooves  21   b  of the upper stem  21  are opened. The lower end portion of the upper stem  21  is opposed in a spaced manner to upper end portions of protruded rib portions  32   a  that are provided on the outer circumferential surface of the inner slide cylinder  32 . 
     In a part of the outer circumferential surface of the lower stem  20  that is inserted into the inner slide cylinder  32 , a plurality of stem grooves  20   a  are formed that extend in the up-down direction. In the outer circumferential surface of the inner slide cylinder  32 , a plurality of protrusions are provided, and the stem groove  20   a  is formed between the protrusions. The stem grooves  20   a  are spaced from each other in the circumferential direction. Upper end portions of the stem grooves  20   a  are in communication with the communication gap S. 
     The air-liquid mixing chamber  29  is provided between the lower stem  20  and the upper stem  21 . In the example shown in the figures, the air-liquid mixing chamber  29  is provided between the presser member  24  and the upper stem  21  (in the vicinity of the reduced-diameter part  21   a ). The air-liquid mixing chamber  29  is communicable with the inside of the cylinder for air  28  through an air passage  36  that is made of the longitudinal grooves  21   b , the communication gap S, and the stem grooves  20   a.    
     Here, in the present embodiment, around a part of the lower stem  20  that is located in the cylinder for air  28 , an annular protrusion portion  37  is provided that protrudes outwardly in the radial direction. An upper surface portion of the protrusion portion  37  is in contact with a lower edge of the inner slide cylinder  32  of the piston for air  27 . Therefore, opening sections of the air passage  36  in the cylinder for air  28  are closed, and hence, the communication between the inside of the cylinder for air  28  and the air-liquid mixing chamber  29  is blocked. 
     The piston for liquid  25  is formed in a multistage cylindrical shape whose diameter decreases gradually from the lower end to the upper end thereof. The piston for liquid  25  includes: an upper-side cylindrical portion  25   a  that is fitted into the stem  12  in a liquid-tight state; and a lower-side cylindrical portion  25   b  that protrudes downwardly from a lower-end opening edge of the stem  12  and is fitted into the cylinder for liquid  26  so as to be freely slidable in the up-down direction. 
     Between the upper-side cylindrical portion  25   a  and an inner surface of the lower end portion of the cylinder for liquid  26 , a coil spring  38  is disposed that supports the piston for liquid  25  so as to be slidable in the downwardly in a state with the piston for liquid  25  being biased upwardly. 
     Inside the piston for liquid  25  and the cylinder for liquid  26 , a rod-like valve member  39  is provided that extends in the up-down direction. An upper end portion of the valve member  39  functions as an upper valve body  39   a  that is seatable on/detachable from an upper opening section of the upper-side cylindrical portion  25   a  of the piston for liquid  25 . A lower end portion of the valve member  39  functions as a lower valve body  39   b  that is seatable on/detachable from a lower opening section in the cylinder for liquid  26 . 
     As shown in  FIG. 2 , the foaming member  30  is provided in the stem  12 . In the example shown in the figure, the foaming member  30  is fitted into an upper end portion of the upper stem  21 . The foaming member  30  is made of a plurality of (two, in the example shown in the figure) foaming elements  30   a  aligned in the up-down direction. The foaming element  30   a  is made of a cylinder in which a net body is provided over an opening end edge thereof. Of the two foaming elements  30   a , the foaming element  30   a  on the upper side is provided with a net body only over an upper-end opening edge of the cylinder of two opening edges while the foaming element  30   a  on the lower side is provided with a net body only over a lower-end opening edge of the cylinder of two opening edges. Note that the number of the foaming elements  30   a  may be at least one. Furthermore, with the net body of the foaming element  30   a  (small mesh) located on the upper side and the net body of the foaming element  30   a  (large mesh) located on the lower side being altered in the mesh size, it is possible to produce finer foam. 
     As shown in  FIG. 2  to  FIG. 4 , the depressing head  15  includes: a head main unit  41 ; and an exterior cylindrical portion  42 . The head main unit  41  and the exterior cylindrical portion  42  are formed as separate entities, and are fitted to each other. The head main unit  41  includes: a top wall portion  43 ; an attachment cylindrical portion  44 ; a fitting cylindrical portion  45 ; a covering wall portion  46 ; and a nozzle cylindrical portion  47 . The top wall portion  43  is arranged above the stem  12 . 
     The attachment cylindrical portion  44  extends downwardly from the top wall portion  43  and is attached to the stem  12 . The attachment cylindrical portion  44  is arranged coaxially with the axis line O, and is fitted onto the upper end portion of the upper stem  21 . 
     A lower end portion of the attachment cylindrical portion  44  is inserted into the guide cylindrical portion  17 . The attachment cylindrical portion  44  is freely movable in the guide cylindrical portion  17  in the up-down direction. 
     On an inner circumferential surface of an upper end portion of the attachment cylindrical portion  44 , restricting ribs  44   a  are provided that protrude inwardly in the radial direction. The restricting rib  44   a  is formed in a plate shape that extends in the up-down direction. Upper end portions of the restricting ribs  44   a  are connected to the top wall portion  43 . Lower end portions of the restricting ribs  44   a  are in contact with the upper end portion of the upper stem  21 . 
     The fitting cylindrical portion  45  protrudes downwardly from the top wall portion  43 , and is arranged coaxially with the axis line O. The fitting cylindrical portion  45  surrounds the upper end portion of the attachment cylindrical portion  44  from the outer side in the radial direction. 
     The nozzle cylindrical portion  47  extends from the attachment cylindrical portion  44  outwardly in the radial direction, and protrudes further outwardly in the radial direction than the fitting cylindrical portion  45 . The inside of the nozzle cylindrical portion  47  is in communication with the inside of the stem  12  through the inside of the upper end portion of the attachment cylindrical portion  44 . In a protrusion end of the nozzle cylindrical portion  47 , a nozzle hole  14  is provided. Hereinafter, in the radial direction, a direction in which the nozzle cylindrical portion  47  extends is referred to as forward-rearward direction. A direction in which the nozzle hole  14  opens along the forward-rearward direction is referred to as forward direction while a direction opposite thereto is referred to as rearward direction. 
     As shown in  FIG. 3 , the covering wall portion  46  extends downwardly from an outer circumferential edge of the top wall portion  43 . The covering wall portion  46  is formed in a C shape that opens toward the forward direction in a planar view when the foamer dispenser  10  is seen in the up-down direction. A circumferential end portion of the covering wall portion  46  is connected to a side surface of the nozzle cylindrical portion  47  along the circumferential direction. The covering wall portion  46  covers the fitting cylindrical portion  45  and the upper end portion of the attachment cylindrical portion  44  from the outer side in the radial direction. 
     As shown in  FIG. 2 , the exterior cylindrical portion  42  is provided at a position below the top wall portion  43 . An upper edge of the exterior cylindrical portion  42  is in contact with a lower surface of the top wall portion  43 . An upper end portion of the exterior cylindrical portion  42  is fitted into the fitting cylindrical portion  45 . On an upper end portion of the exterior cylindrical portion  42 , an annular protruded strip portion  48  is provided that protrudes outwardly in the radial direction. The protruded strip portion  48  is fitted (undercut-fitted or the like) to an inner circumferential surface of the fitting cylindrical portion  45 . 
     The exterior cylindrical portion  42  surrounds the attachment cylindrical portion  44  and the guide cylindrical portion  17  from the outer side in the radial direction. The inside of the exterior cylindrical portion  42  is communicable with the inside of the cylinder for air  28  through the inside of the guide cylindrical portion  17 . A lower end portion of the exterior cylindrical portion  42  is arranged at a position equivalent in the up-down direction to that of the lower end portion of the attachment cylindrical portion  44 . The lower end portion of the exterior cylindrical portion  42  surrounds the upper end portion of the guide cylindrical portion  17  from the outer side in the radial direction. 
     On the lower end portion of the exterior cylindrical portion  42 , an outer guide protrusion  42   a  is provided that protrudes inwardly in the radial direction. The outer guide protrusion  42   a  is formed in an annular shape. In a state before the depressing head  15  is depressed, the outer guide protrusion  42   a  faces the inner guide protrusion  17   a  in the radial direction and is close to the inner guide protrusion  17   a.    
     As shown in  FIG. 2  to  FIG. 7 , in the upper end portion of the exterior cylindrical portion  42 , intake holes  51   a ,  51   b  are formed. The intake holes  51   a ,  51   b  penetrate through the exterior cylindrical portion  42  in the radial direction, and open toward the upward direction. Hereinafter, the intake hole  51   a  is referred to also as first intake hole  51   a  while the intake hole  51   b  is referred to also as second intake hole  51   b.    
     As shown in  FIG. 3  and  FIG. 5 , two first intake holes  51   a  are arranged in sections of the exterior cylindrical portion  42  that are located on both sides in the left-right direction, which is orthogonal to both of the up-down direction and the forward-rearward direction. 
     The two first intake holes  51   a  are formed so as to have equivalent shape and size. As shown in  FIG. 7 , the first intake hole  51   a  is formed so as to have a rectangular shape in a side view when the foamer dispenser  10  is seen in the left-right direction. 
     Here, in opening circumferential edges of the intake holes  51   a ,  51   b  in the outer circumferential surface of the exterior cylindrical portion  42 , receding sections  52  are formed that recede inwardly in the radial direction and are continuous to the intake holes  51   a ,  51   b . The receding section  52  is arranged in a part, of the opening circumferential edge of the first intake hole  51   a  in the outer circumferential surface of the exterior cylindrical portion  42 , that continues to the first intake hole  51   a  from below. The receding section  52  is formed in a rectangular shape when seen in a side view. The size of the receding section  52  in the circumferential direction is equivalent to that of the first intake hole  51   a  in the circumferential direction. 
     As shown in  FIG. 4 , the first intake holes  51   a  are covered with the fitting cylindrical portion  45  and the covering wall portion  46  from the outer side in the radial direction. The first intake hole  51   a  is in communication with the outside of the foamer dispenser  10  through the receding section  52 . 
     As shown in  FIG. 2 ,  FIG. 3 , and  FIG. 5 , the second intake hole  51   b  is located on the forward side in the exterior cylindrical portion  42 . The second intake hole  51   b  is arranged so that the position of the second intake hole  51   b  in the circumferential direction coincides with that of the nozzle cylindrical portion  47 . 
     Into the second intake hole  51   b , the nozzle cylindrical portion  47  is inserted from above. The nozzle cylindrical portion  47  extends forwardly from the second intake hole  51   b , and protrudes further outwardly in the radial direction than the exterior cylindrical portion  42 . A size of the second intake hole  51   b  in the circumferential direction is equivalent to that of the nozzle cylindrical portion  47  in the circumferential direction. A side surface of the nozzle cylindrical portion  47  is locked between parts of an inner circumferential edge of the second intake hole  51   b  that face inwardly in the circumferential direction. 
     The second intake hole  51   b  is larger than the nozzle cylindrical portion  47  in the up-down direction. Therefore, between a lower surface of the nozzle cylindrical portion  47  and a part of the inner circumferential edge of the second intake hole  51   b  that faces upwardly, a gap in the up-down direction is provided. 
     On an inner circumferential surface of the exterior cylindrical portion  42 , guide ribs  53   a ,  53   b  are protrudingly provided that extend in the up-down direction. When the depressing head  15  is depressed obliquely, the guide ribs  53   a ,  53   b  are capable of slidably contacting the guide cylindrical portion  17  (the inner guide protrusion  17   a  of the guide cylindrical portion  17 , in the example shown in the figures) from the outer side in the radial direction. The guide ribs  53   a  and the guide ribs  53   b  are arranged in sections of the exterior cylindrical portion  42  that are opposite to each other in the radial direction across the guide cylindrical portion  17 . Hereinafter, the guide rib  53   a  is referred to also as first guide rib  53   a  while the guide rib  53   b  is referred to also as second guide rib  53   b.    
     The first guide ribs  53   a  are arranged in a forward section of the exterior cylindrical portion  42 . To be more specific, the first guide ribs  53   a  are arranged in a section beneath the second intake hole  51   b . Upper end portions of the first guide ribs  53   a  are located on the side lower than the inner circumferential edge of the second intake hole  51   b . Lower end portions of the first guide ribs  53   a  are connected to the outer guide protrusion  42   a . The first guide ribs  53   a  extend straightly in the up-down direction, and are connected smoothly to a surface of the outer guide protrusion  42   a.    
     As shown in  FIG. 5 , three first guide ribs  53   a  are spaced in the circumferential direction in the forward section of the exterior cylindrical portion  42 . The three first guide ribs  53   a  are arranged at regular intervals in the circumferential direction. Of the three first guide ribs  53   a , the one located in the middle in the circumferential direction is arranged right in the forward direction with respect to the axis line O. 
     The second guide ribs  53   b  are arranged in a rear section, which is a section located on a side opposite to the first guide ribs  53   a  in the radial direction. As shown in  FIG. 6 , the second guide rib  53   b  is formed over the whole length of the rear section of the exterior cylindrical portion  42  in the up-down direction. Lower end portions of the second guide ribs  53   b  are connected to the outer guide protrusion  42   a . The second guide ribs  53   b  extend straightly in the up-down direction, and are connected smoothly to a surface of the outer guide protrusion  42   a.    
     As shown in  FIG. 5 , two second guide ribs  53   b  are spaced in the circumferential direction in the rear section of the exterior cylindrical portion  42 . The two second guide ribs  53   b  are arranged to avoid a part of the exterior cylindrical portion  42  that is located right in the rear direction with respect to the axis line O. 
     As shown in  FIG. 3  and  FIG. 4 , on the top wall portion  43  of the head main unit  41 , pairs of lock portions  54  are provided that protrude downwardly and are spaced from each other in the circumferential direction. The pairs of lock portions  54  are each locked between parts of an inner circumferential edge of each of the intake holes  51   a ,  51   b  that face inwardly in the circumferential direction. 
     The pairs of lock portions  54  are each provided in each of the two first intake holes  51   a , and are arranged in parts of the top wall portion  43  that are located on both sides in the left-right direction. The lock portion  54  is formed in a plate shape that extends in the radial direction. The lock portion  54  extends straightly along the left-right direction when seen in a planar view. Surfaces of the paired lock portions  54  that face in the circumferential direction are locked in the inner circumferential edge of the first intake hole  51   a , and are close to or in contact with the inner circumferential edge of the first intake hole  51   a.    
     The lock portion  54  connects between the attachment cylindrical portion  44  and the fitting cylindrical portion  45 . To be more specific, an end section of the lock portion  54  on the inner side in the radial direction is connected to the attachment cylindrical portion  44  while an end section thereof on the outer side in the radial direction is connected to the fitting cylindrical portion  45 . 
     As shown in  FIG. 4 , a size of the lock portion  54  in the up-down direction is smaller in a stepwise manner from the inner side to the outer side in the radial direction. Of the lock portion  54 , an in-cylinder portion  54   a , which is located inner in the radial direction than the exterior cylindrical portion  42  in the radial direction, protrudes further downwardly than a part that is located outer in the radial direction than the in-cylinder portion  54   a  and that is arranged in the first intake hole  51   a . The in-cylinder portion  54   a  supports the exterior cylindrical portion  42  from the inner side in the radial direction. The in-cylinder portion  54   a  is close to or in contact with the inner circumferential surface of the exterior cylindrical portion  42  from the inner side in the radial direction. 
     As shown in  FIG. 2  and  FIG. 3 , the top wall portion  43  is provided with a plurality of support plate portions  55  that protrude downwardly and extend in the radial direction. The support plate portions  55  are arranged in the circumferential direction. The support plate portions  55  are provided radially about the axis line O when seen in a planar view, and are arranged at intervals over the whole length in the circumferential direction. The support plate portions  55  are arranged at positions that avoid, in the circumferential direction, the nozzle cylindrical portion  47  and a section between each pair of lock portions  54 . 
     As shown in  FIG. 2 , end sections of the support plate portions  55  on the inner side in the radial direction are connected to the attachment cylindrical portion  44 . End sections of the support plate portions  55  on the outer side in the radial direction support the exterior cylindrical portion  42  from the inner side in the radial direction, and are close to or in contact with the inner circumferential surface of the exterior cylindrical portion  42  from the inner side in the radial direction. As shown in  FIG. 3 , the support plate portions  55  are spaced in the circumferential direction, to thereby constitute a plate portion train  56 . The exterior cylindrical portion  42  is fitted onto the plate portion train  56 . 
     In the foamer dispenser  10  as shown in  FIG. 1  and  FIG. 2 , when the content substance is discharged, the restricting member  19  is removed and the depressing head  15  is depressed. Then, the guide cylindrical portion  17  moves into a gap between the attachment cylindrical portion  44  and the exterior cylindrical portion  42 . 
     In the present embodiment, the nozzle cylindrical portion  47  protrudes from the attachment cylindrical portion  44  toward the forward direction. Therefore, in depressing the depressing head  15  with, for example, the nozzle cylindrical portion  47  being held, the depressing head  15  may be depressed in an obliquely forward or rearward direction, not in a straightly downward direction. This makes the positional relationship between the exterior cylindrical portion  42  and the head main unit  41  in the forward-rearward direction likely to be unstable. However, the first guide ribs  53   a  and the second guide ribs  53   b  are arranged in the sections of the exterior cylindrical portion  42  that are located on both sides in the forward-rearward direction. Therefore, when the depressing head  15  is depressed, the guide ribs  53   a ,  53   b  stabilize the position of the exterior cylindrical portion  42  in the forward-rearward direction. 
     Here, when the depressing head  15  is depressed as described above, the guide cylindrical portion  17  moves into the gap between the attachment cylindrical portion  44  and the exterior cylindrical portion  42 . Then, the stem  12  and the piston for liquid  25  moves downwardly while compressing and deforming the coil spring  38  in the up-down direction. 
     At this time, a gap is formed between the lower end of the inner slide cylinder  32  and a top surface of the protrusion portion  37  of the stem  12 . As a result, the inside of the cylinder for air  28  and the inside of the air-liquid mixing chamber  29  are in communication with each other through the air passage  36 . 
     Furthermore, at this time, with the downward movement of the piston for liquid  25 , the upper end portion of the piston for liquid  25  is detached from the upper valve body  39   a  of the valve member  39  in the downward direction. This causes the inside of the cylinder for liquid  26  and the inside of the stem  12  to be in communication with each other. Furthermore, the lower valve body  39   b  of the valve member  39  is also moved downwardly. As a result, the lower valve body  39   b  is seated on the lower opening section in the cylinder for liquid  26 , and closes it. 
     When the depressing head  15  is further depressed, the piston for air  27  is also moved downwardly in a state with the air hole  34  being closed by the valve body  35 . This compresses the air in a lower chamber in the cylinder for air  28  that is located beneath the piston for air  27 . As a result, the air in the lower chamber flows through the gap between the lower end of the inner slide cylinder  32  in the piston for air  27  and the protrusion portion  37  of the stem  12  into the air passage  36 , and is then transferred to the air-liquid mixing chamber  29 . 
     Furthermore, at this time, in a state with the lower opening section of the cylinder for liquid  26  being closed by the lower valve body  39   b  of the valve member  39 , the piston for liquid  25  moves downwardly. Therefore, the liquid in the cylinder for liquid  26  rises and reaches the inside of the stem  12 . Then, a liquid pressure in the cylinder for liquid  26  acts on the liquid discharge valve  23  in the stem  12  to cause the liquid discharge valve  23  to be detached from the valve seat  22  upwardly. Thereby, the liquid in the cylinder for liquid  26  flows into the air-liquid mixing chamber  29 . 
     After the liquid and the air, which have been joined together in the air-liquid mixing chamber  29  as described above, are caused to pass through the foaming member  30  to produce foam, the foamed body is caused to pass through the inside of the upper end portion of the attachment cylindrical portion  44  and the inside of the nozzle cylindrical portion  47 . Then, the foam is caused to be discharged from the nozzle hole  14 . 
     After that, when the depressing of the depressing head  15  is released, the piston for liquid  25  is pressed upwardly by the elastic restoring force of the coil spring  38 . As a result, the upper opening section of the upper-side cylindrical portion  25   a  of the piston for liquid  25  is brought into contact with the upper valve body  39   a . This blocks the communication between the inside of the cylinder for liquid  26  and the inside of the stem  12 . Furthermore, the lower valve body  39   b  is detached from the lower opening section in the cylinder for liquid  26 . This causes the inside of the container main unit  1  and the inside of the cylinder for liquid  26  to be in communication with each other. As a result, the content substance in the container main unit  1  flows into the cylinder for liquid  26 . At this time, the inside of the container main unit  1  comes to have a negative pressure. Therefore, through an introduction hole provided in a part of the cylinder for air  28  that is located upper than the outer slide cylinder  31 , the air in an upper chamber of the cylinder for air  28  that is located above the piston for air  27  is introduced into the container main unit  1 . 
     Furthermore, with the piston for liquid  25  rising as described above, the stem  12  and the depressing head  15  rise in a unified manner. With the protrusion portion  37  of the stem  12  being brought into contact with the lower edge of the inner slide cylinder  32  of the piston for air  27 , the communication between the lower chamber and the air-liquid mixing chamber  29  through the air passage  36  is blocked. In this condition, the stem  12  and the piston for air  27  rise in a unified manner to decrease the pressure in the lower chamber. This opens the valve body  35  to open the air hole  34 . As a result, outside air is sucked into the lower chamber through the inside of the intake holes  51   a ,  51   b , the inside of the exterior cylindrical portion  42 , and the inside of the guide cylindrical portion  17 . 
     Here, for example in a foamer dispenser in which the exterior cylindrical portion  42  is not provided with the intake holes  51   a ,  51   b , when the depressing head  15  moves back upwardly, outside air is sucked into the exterior cylindrical portion  42  through a gap between the inner circumferential surface of the exterior cylindrical portion  42  and the outer circumferential surface of the guide cylindrical portion  17  (hereinafter, referred to as “cylinder-cylinder gap”), and is then drawn into the cylinder for air  28  through the inside of the guide cylindrical portion  17 . If foreign matter such as water is attached to an external surface of the attachment cap  11 , there is a possibility that, when the depressing head  15  moves back upwardly, the foreign matter together with the air is drawn into the exterior cylindrical portion  42  through the cylinder-cylinder gap and further into the cylinder for air  28 . 
     On the other hand, in the foamer dispenser  10  of the present embodiment, the intake holes  51   a ,  51   b  are formed in the upper end portion of the exterior cylindrical portion  42 . Therefore, when the depressing of the depressing head  15  is released to cause the inside the cylinder for air  28  to have a negative pressure, it is possible to suck the outside air into the exterior cylindrical portion  42  through the intake holes  51   a ,  51   b  as described above. As a result, sucking of the outside air into the exterior cylindrical portion  42  through the cylinder-cylinder gap is inhibited, and hence, sucking of foreign matter together with the outside air into the exterior cylindrical portion  42  through the cylinder-cylinder gap is inhibited. 
     As described above, according to the foamer dispenser  10  of the present embodiment, the intake holes  51   a ,  51   b  are formed in the upper end portion of the exterior cylindrical portion  42 . Therefore, as described above, it is possible to inhibit the sucking of the outside air together with foreign matter into the exterior cylindrical portion  42  through the cylinder-cylinder gap, and hence, it is possible to inhibit the intrusion of foreign matter into the cylinder for air  28 . 
     Furthermore, the intake holes  51   a ,  51   b  are formed in the upper end portion of the exterior cylindrical portion  42 . Therefore, it is possible to maintain a low influence that the intake holes  51   a ,  51   b  have on the appearance of the depressing head  15 . 
     Furthermore, the intake holes  51   a ,  51   b  open toward the upward direction. Therefore, for example, when the exterior cylindrical portion  42  is molded with a mold, it is possible to remove the mold with ease, and hence, to make it easy to form the foamer dispenser  10  in a simplified manner. 
     Furthermore, the receding sections  52  are formed in the opening circumferential edges of the intake holes  51   a ,  51   b  in the outer circumferential surface of the exterior cylindrical portion  42 . This makes it difficult for foreign matter such as water to intrude. Furthermore, it is possible to introduce outside air into the intake holes  51   a ,  51   b  through the receding sections  52 , and hence, to effectively suck the outside air into the exterior cylindrical portion  42  through the intake holes  51   a ,  51   b.    
     Furthermore, the head main unit  41  includes the covering wall portion  46 . Therefore, it is possible to inhibit the intake holes  51   a ,  51   b  from being exposed to the outside, and hence, to maintain the appearance of the foamer dispenser  10  favorable. 
     Furthermore, the top wall portion  43  is provided with the pairs of lock portions  54 . Therefore, when the head main unit  41  and the exterior cylindrical portion  42  are to rotate relatively to each other in the circumferential direction, the lock portions  54  are locked in the inner circumferential edges of the intake holes  51   a ,  51   b , to thereby make it possible to restrict the rotation. Furthermore, when the exterior cylindrical portion  42  is to be deformed so that the intake holes  51   a ,  51   b  are narrowed in the circumferential direction, the lock portions  54  are locked in the inner circumferential edges of the intake holes  51   a ,  51   b . Thereby, it is possible to restrict the deformation. 
     Furthermore, the pairs of lock portions  54  are spaced in the circumferential direction. Therefore, while the rotation and deformation as described above is being restricted, it is possible to securely bring the inside and outside of the exterior cylindrical portion  42  into communication with each other through the parts of the intake holes  51   a ,  51   b  that are located between the paired lock portions  54 . Consequently, it is possible to securely suck the outside air into the exterior cylindrical portion  42  through the intake holes  51   a ,  51   b.    
     In the present embodiment, the top wall portion  43  is provided with the fitting cylindrical portion  45  that protrudes downwardly and that is fitted onto the attachment cylindrical portion  44 , and the lock portions  54  connect between the attachment cylindrical portion  44  and the fitting cylindrical portion  45 . In this case, when the lock portions  54  are locked in the inner circumferential edges of the intake holes  51   a ,  51   b , it is possible to support both ends of the lock portions  54  in the radial direction by means of the attachment cylindrical portion  44  and the fitting cylindrical portion  45 . Therefore, it is possible to effectively restrict the aforementioned rotation and deformation. 
     Furthermore, the plurality of support plate portions  55  are arranged in the top wall portion  43 , and moreover, the ends of the support plate portions  55  on the inner side in the radial direction are connected to the attachment cylindrical portion  44  while the ends of the support plate portions  55  on the outer side in the radial direction support the exterior cylindrical portion  42  from the inner side in the radial direction. Therefore, for example, when the exterior cylindrical portion  42  is about to shake in the radial direction with respects to the head main unit  41 , it is possible to cause the top wall portion  43  and the attachment cylindrical portion  44  to support the exterior cylindrical portion  42  via the support plate portions  55 . Therefore, it is possible to attach the exterior cylindrical portion  42  tightly to the head main unit  41 . Consequently, for example, it is possible to inhibit shaking between the exterior cylindrical portion  42  and the head main unit  41 . 
     Furthermore, the top wall portion  43  is provided with the fitting cylindrical portion  45 . This makes it possible to sandwich the exterior cylindrical portion  42  between the support plate portions  55  and the fitting cylindrical portion  45  in the radial direction. Therefore, it is possible to attach the exterior cylindrical portion  42  further tightly to the head main unit  41 . 
     Furthermore, the in-cylinder portions  54   a  of the lock portions  54  support the exterior cylindrical portion  42  from the inner side in the radial direction. This makes it possible to support the exterior cylindrical portion  42  from the inner side in the radial direction not only by the support plate portions  55  but also by the in-cylinder portions  54   a  of the lock portions  54 . Therefore, it is possible to attach the exterior cylindrical portion  42  further tightly to the head main unit  41 . 
     Furthermore, the guide ribs  53   a ,  53   b  are protrudingly provided on the inner circumferential surface of the exterior cylindrical portion  42 . Therefore, for example, when the depressing head  15  is obliquely depressed, the guide cylindrical portion  17  is made slidable on the guide ribs  53   a ,  53   b  in the up-down direction, and hence, it is possible to restrict the displacement of the exterior cylindrical portion  42  in the radial direction by means of the guide cylindrical portion  17 . As a result, it is possible to stabilize the position of the exterior cylindrical portion  42  in the radial direction. Consequently, it is possible to stabilize the positional relationship between the exterior cylindrical portion  42  and the head main unit  41  in the radial direction. 
     Furthermore, the guide ribs  53   a ,  53   b  are arranged in the sections of the exterior cylindrical portion  42  that are opposite to each other in the radial direction across the guide cylindrical portion  17 . Therefore, when the depressing head  15  is obliquely depressed, the guide ribs  53   a ,  53   b  are made capable of slidably contacting the guide cylindrical portion  17  from both outer sides in the radial direction. Consequently, it is possible to further stabilize the position of the exterior cylindrical portion  42  in the radial direction. 
     Furthermore, the first guide ribs  53   a  and the second guide ribs  53   b  are arranged in the sections of the exterior cylindrical portion  42  that are located on both sides in the forward-rearward direction. Therefore, when the depressing head  15  is obliquely depressed, it is possible to stabilize the position of the exterior cylindrical portion  42  in the forward-rearward direction by means of the first guide ribs  53   a  and the second guide ribs  53   b . Therefore, it is possible to securely stabilize the positional relationship between the exterior cylindrical portion  42  and the head main unit  41  in the forward-rearward direction. 
     The technical scope of the present invention is not limited to the aforementioned embodiment. Various modifications can be made without departing from the spirit or scope of the present invention. 
     For example, in a modification of the present invention, the restricting member  19  may not be provided. 
     In the aforementioned embodiment, the first guide ribs  53   a  and the second guide ribs  53   b  are provided. However, the present invention is not limited to this. For example, guide ribs may be arranged in sections of the exterior cylindrical portion that are located on both sides in the left-right direction. 
     In a modification of the present invention, the guide ribs  53   a ,  53   b  may not be arranged in the sections of the exterior cylindrical portion  42  that are opposite to each other in the radial direction across the guide cylindrical portion  17 . Furthermore, the guide ribs  53   a ,  53   b  may not be provided. 
     In a modification of the present invention, the in-cylinder portions  54   a  of the lock portions  54  may not support the exterior cylindrical portion  42  from the inner side in the radial direction. Furthermore, the lock portions  54  may not connect between the attachment cylindrical portion  44  and the fitting cylindrical portion  45 . Furthermore, the lock portion  54  may not be provided. 
     In a modification of the present invention, the nozzle cylindrical portion  47 , the fitting cylindrical portion  45 , and the covering wall portion  46  may not be provided. In this case, for example, the nozzle hole may be made of a through-hole that penetrates through the exterior cylindrical portion. Furthermore, the support plate portion  55  may not be provided. 
     In a modification of the present invention, the receding sections  52  may not be provided. 
     In the aforementioned embodiment, the first intake holes  51   a  and the second intake hole  51   b  are provided. However, the present invention is not limited to this. For example, as intake hole(s), at least either the first intake holes or the second intake hole may be provided. 
     (Second Embodiment) 
     Hereunder is a description of a discharge vessel  110  including a foamer dispenser  101  according to a second embodiment of the present invention, with reference to  FIG. 8 . 
     As shown in  FIG. 8 , the discharge vessel  110  includes: a foamer dispenser  101  and a container main unit  102 . In the container main unit  102 , a liquid-like content substance (content liquid) is contained. The foamer dispenser  101  transforms the content substance in the container main unit  102  into a bubble form and discharges it to the outside of the container. As the content substance, for example a skin wash fluid (body-wash) may be listed. For an exemplary content substance, the component table as shown in Table 1 described above is used. 
     In  FIG. 8 , the foamer dispenser  101  includes: an attachment cap  104  attached to a mouth portion  103  of a container main unit  102  in which a content substance is contained; and a discharge device  108  with a stem  105  and with a depressing head  107 . The stem  105  is erected through the attachment cap  104  so as to be movable downwardly while being biased upwardly. The depressing head  107 is attached to the stem  105  and a discharge hole  106  is formed in the depressing head  107 . The discharge device  108  includes: a piston for liquid  111 ; a cylinder for liquid  112 ; a piston for air  113 ; a cylinder for air  114 ; an air-liquid mixing chamber  115 ; and a foaming member  116 . The piston for liquid  111  moves in the up-down direction in conjunction with the stem  105 . Inside the cylinder for liquid  112 , the piston for liquid  111  is disposed so as to be slidable in the up-down direction. The piston for air  113  moves in the up-down direction in conjunction with the stem  105 . Inside the cylinder for air  114 , the piston for air  113  is disposed so as to be slidable in the up-down direction. The air-liquid mixing chamber  115  mixes the content substance transferred from the cylinder for liquid  112  with the air transferred from the cylinder for air  114 . The foaming member  116  is disposed between the air-liquid mixing chamber  115  and the discharge hole  106 , and foams the air-liquid mixture that has been mixed in the air-liquid mixing chamber  115 . The piston for liquid  111 , the cylinder for liquid  112 , the piston for air  113 , the cylinder for air  114 , the air-liquid mixing chamber  115 , and the foaming member  116  constitute a discharge mechanism of the discharge device  108 . 
     In the foamer dispenser  101 , the depressing head  107  is depressed with respect to the container main unit  102  to move the stem  105  downwardly, to thereby activate the discharge mechanism. As a result, the content substance in the container main unit  102  is transferred upwardly and is mixed with air. The bubble-like content substance, which is a foamed air-liquid mixture obtained in this manner, is discharged from the discharge hole  106  of the depressing head  107  toward a side of the container. 
     In  FIG. 8 , the mouth portion  103  of the container main unit  102 , the attachment cap  104 , the stem  105 , and the depressing head  107  have their central axis lines arranged on a common axis. Hereinafter, the common axis is referred to as axis line O, a direction on the side of the depressing head  107  along the axis line O direction (upper side in  FIG. 8 ) is referred to as upper direction while a direction on the side of a bottom portion of the container main unit  102  (lower side in  FIG. 8 ) is referred to as lower direction. Furthermore, a direction that is orthogonal to the axis line O is referred to as radial direction while a direction about the axis line O is referred to as circumferential direction. 
     The attachment cap  104  includes: a circumferential wall portion (attachment circumferential wall portion)  117  that is attached to the mouth portion  103  of the container main unit  102 ; and a guide portion  118  which continues to an inner side of the circumferential wall portion  117  in the radial direction and through which the discharge device  108  is inserted in the up-down direction. 
     In the example shown in the figure, the circumferential wall portion  117  is detachably attached to the mouth portion  103  by screwing. The circumferential wall portion  117  may be attached to the mouth portion  103  by, for example, undercut-fitting or the like instead of screwing. Furthermore, the guide portion  118  includes: an annular ceiling wall portion  119  which is arranged above the mouth portion  103  and through which the stem  105  is inserted; and a guide cylindrical portion  120  that is erected on an inner circumferential edge of the ceiling wall portion  119 . To be more specific, the guide cylindrical portion  120  has a smaller diameter than that of the circumferential wall portion  117 , and besides, an upper end portion of the circumferential wall portion  117  and a lower end portion of the guide cylindrical portion  120  are connected to each other via an annular-plate-like ceiling wall portion  119 . 
     On the ceiling wall portion  119 , a plurality of ribs  121  that protrude downwardly and extend in the radial direction are spaced in the circumferential direction. Furthermore, on the inner circumferential edge of the ceiling wall portion  119 , an insertion cylinder  122  is provided so as to extend downwardly from the inner circumferential edge of the ceiling wall portion  119 , and inner ends of the ribs  121  in the radial direction are connected to an outer circumferential surface of the insertion cylinder  122 . In the example shown in the figure, the insertion cylinder  122  of the ceiling wall portion  119  has an inner diameter smaller than that of the guide cylindrical portion  120 . 
     On the upper end portion of the guide cylindrical portion  120 , an annular inner guide protrusion  123  is formed that protrudes outwardly along the circumferential direction and extends along the circumferential direction. To a part of the guide cylindrical portion  120  that is located beneath the inner guide protrusion  123 , a restricting member  124  is attached that restricts a downward movement of the depressing head  107  with respect to the guide cylindrical portion  120 . The restricting member  124  has a C shape in a top view when the foamer dispenser  101  is seen from above, and is detachably fitted onto the guide cylindrical portion  120 . 
     On the inner circumferential surface of the guide cylindrical portion  120 , guide ribs  125  are provided that protrude inwardly in the radial direction and extend along the up-down direction. As the guide ribs  125 , the foamer dispenser  101  of the present embodiment has third guide ribs  131  and fourth guide ribs  132 , which will be described later. The guide ribs  125  provided on the guide cylindrical portion  120  are the fourth guide ribs  132 . 
     In the foamer dispenser  101 , either one of an outer circumferential surface of an insertion section of the discharge device  108  that is inserted through the guide portion  118  and an inner circumferential surface of the guide portion  118  is provided with the guide ribs  125  that are slidable with respect to the other in the up-down direction. The fourth guide ribs  132  are provided on either one of the guide cylindrical portion  120  and an attachment cylindrical portion  157  (described later) of the depressing head  107  so as to be slidable with respect to the other. In the present embodiment, the fourth guide ribs  132  are formed on the guide cylindrical portion  120  so as to be slidable in the up-down direction with respect to the attachment cylindrical portion  157 . 
     The cylinder for air  114  is formed in a cylindrical shape with a circumferential wall and a bottom wall. On an upper opening section of the circumferential wall, a flange is formed that protrudes outwardly in the radial direction and extends along the circumferential direction. Sandwiched between packing provided on a top surface of the mouth portion  103  of the container main unit  102  and the ceiling wall portion  119  of the attachment cap  104  in the up-down direction, the cylinder for air  114  is fixed to the container main unit  102  and the attachment cap  104 . The bottom wall of the cylinder for air  114  is further inclined toward the upper direction as it is closer to the inner side in the radial direction. 
     The cylinder for liquid  112  is formed integrally with the cylinder for air  114 . The cylinder for liquid  112  includes: a base cylindrical portion  126  that extends downwardly from an inner circumferential edge of the bottom wall of the cylinder for air  114 ; a tapered cylindrical portion  127  that is connected to a lower end of the base cylindrical portion  126  so as to extend downwardly and has a diameter that gradually decreases as it extends further downwardly; and a pendant cylindrical portion  128  that is connected to a lower end of the tapered cylindrical portion  127  so as to extend downwardly. On an inner circumferential surface of a section of the cylinder for liquid  112  at which the base cylindrical portion  126  and the tapered cylindrical portion  127  are connected, a plurality of longitudinal ribs are protrudingly provided that extend in the up-down direction. The longitudinal ribs are spaced in the circumferential direction. Into the pendant cylindrical portion  128 , a suction pipe is fitted that extends toward a bottom portion of the container main unit  102 . 
     In the cylinder for liquid  112 , the piston for liquid  111  is disposed so as to be freely slidably in the up-down direction. The piston for liquid  111  is linked to the stem  105 . To be more specific, the piston for liquid  111  is linked to the stem  105  so as to move in the up-down direction together with the stem  105 . The piston for liquid  111  is formed in a cylindrical shape. In a lower end portion of the piston for liquid  111 , a large-diameter section  129  is provided that is fitted into the cylinder for liquid  112  so as to be slidable in the up-down direction in a liquid-tight state. In an upper end portion of the piston for liquid  111 , a small-diameter section  130  is provided that is detachably fitted to an upper valve body  136  of a valve member  135 . In a middle part of the piston for liquid  111  that is located between the lower end portion and the upper end portion, a middle-diameter section  133  is provided that connects between the large-diameter section  129  and the small-diameter section  130 . 
     The piston for liquid  111  is biased upwardly by a biasing member  134  that is provided between the upper end portion of the piston for liquid  111  and the longitudinal ribs of the cylinder for liquid  112 . As the biasing member  134 , for example a coil spring or a resin spring may be adopted. 
     Through the cylinder for liquid  112 , the piston for liquid  111 , and the biasing member  134 , the rod-like valve member  135  is inserted so as to be movable in the up-down direction. In an upper end portion of the valve member  135 , the upper valve body  136  with an inverted hollow conical shape is formed. In a lower end portion of the valve member  135 , a lower valve body  137  is formed. The upper valve body  136  is spaceably seated on a valve seat portion, which is formed in the upper end portion (small-diameter section  130 ) of the piston for liquid  111 , from above the valve seat portion. The lower valve body  137  is upwardly spaced away from the tapered cylindrical portion  127  of the cylinder for liquid  112 , and is seatable on the tapered cylindrical portion  127 . On an outer circumferential surface of the lower valve body  137 , guide protrusions are protrudingly provided, each of which is disposed between the adjacent longitudinal ribs of the cylinder for liquid  112 . 
     The stem  105  is provided so as to be movable downwardly in the mouth portion  103  of the container main unit  102  while being biased upwardly. The stem  105  includes: a lower stem  138 ; and an upper stem  139 . The lower stem  138  and the upper stem  139  are both formed in a cylindrical shape. 
     The lower stem  138  is inserted through the cylinder for air  114 . The lower stem  138  is formed so that the lower portion thereof has a larger diameter than that of the upper portion thereof. The lower portion of the lower stem  138  is fitted onto the middle-diameter section  133  of the piston for liquid  111  while a lower end portion of the upper portion of the lower stem  138  is fitted onto the small-diameter section  130  of the piston for liquid  111 . On a connection part of the lower stem  138  between the upper portion and the lower portion, an annular flange portion  140  is provided that protrudes outwardly in the radial direction and extends along the circumferential direction. Furthermore, on a part of the upper portion of the lower stem  138  that is upper than the connection part, an annular valve seat  141  is provided that protrudes inwardly in the radial direction and extends along the circumferential direction. On the valve seat  141 , a liquid discharge valve  151  with a spherical shape is seated so as to be upwardly spaceable. 
     An upper end portion of the lower stem  138  is arranged in the guide cylindrical portion  120 . In the upper end portion of the lower stem  138 , a presser member  142  having a cylindrical shape with a top is provided. The presser member  142  is formed via support pillars. The presser member  142  is mounted on the valve seat  141 , and is undercut-fitted between the lower stem  138  and the valve seat  141 . Between the support pillars of the presser member  142 , a circulation hole is opened that penetrates through the corresponding support pillar in the radial direction. On a ceiling wall of the presser member  142 , an upper cylinder is provided toward the upper direction and a lower cylinder is provided toward the lower direction. 
     The upper stem  139  is inserted into the guide cylindrical portion  120  of the attachment cap  104 , and is fitted onto the upper end portion of the lower stem  138 . The lower end portion of the upper stem  139  has an inner diameter larger than that of an out-fitted part of the upper stem  139  that is located upper than the lower end portion and that is fitted onto the upper end portion of the lower stem  138 . In a middle part of the upper stem  139  that is located between the lower end portion and the upper end portion, a reduced-diameter part  143  is formed that has an inner diameter smaller than those of other parts. 
     In a part of the inner circumferential surface of the upper stem  139  that is located lower than the reduced-diameter part  143 , longitudinal grooves  144  are formed that extend in the up-down direction. Upper end portions of the longitudinal grooves  144  open inwardly in the radial direction to be in communication with the air-liquid mixing chamber  115  while lower end portions of the longitudinal grooves  144  open downwardly. 
     The piston for air  113  is disposed in the cylinder for air  114  so as to be freely slidable in the up-down direction. 
     The piston for air  113  is linked to the stem  105 . To be more specific, the piston for air  113  is movable in the up-down direction correspondingly to the movement of the stem  105  in the up-down direction, and is also movable in the up-down direction with respect to the stem  105 . 
     The piston for air  113  includes: an outer slide cylinder  145 ; an inner slide cylinder  146 ; a connector plate  147 ; an air hole  148 ; and a valve body  149 . The outer slide cylinder  145  is fitted to the inside of the cylinder for air  114  so as to be freely slidable in the up-down direction in an airtight state. The inner slide cylinder  146  has a diameter smaller than that of the outer slide cylinder  145 , and is arranged on an inner side of the outer slide cylinder  145  in the radial direction. Furthermore, the inner slide cylinder  146  is fitted onto an upper portion of the lower stem  138  of the stem  105  so as to be slidable in the up-down direction. The connector plate  147  connects between an inner circumferential surface of the outer slide cylinder  145  and an outer circumferential surface of the inner slide cylinder  146 . The air hole  148  penetrates through the connector plate  147  in the up-down direction. The valve body  149  is in contact spaceably with a lower surface of the connector plate  147 , to thereby openably close the air hole  148 . 
     Through the inner slide cylinder  146 , a part of the lower stem  138  that corresponds to the piston for air is inserted so as to be slidable in the up-down direction. The part is located upper than the flange portion  140  and lower than the valve seat  141 . To be more specific, into the inner slide cylinder  146 , a part of the lower stem  138  that corresponds to the piston for air is inserted; and between an inner circumferential surface of the inner slide cylinder  146  and an outer circumferential surface of the part that corresponds to the piston for air, a gap is provided. In the upper portion thereof, the gap is communicable with the inside of the longitudinal grooves  144 . In the lower portion thereof, the gap is communicable with the inside of the cylinder for air  114  through the space between the flange portion  140  and the connector plate  147 . In a state with the inner slide cylinder  146  of the piston for air  113  being seated on the flange portion  140 , the communication between the inside of the cylinder for air  114  and the gap between the inner circumferential surface of the inner slide cylinder  146  and the outer circumferential surface of the part that corresponds to the piston for air is blocked. 
     In the outer circumferential surface of the part of the lower stem  138  that corresponds to the piston for air, a plurality of longitudinal grooves  150  are formed that are spaced in the circumferential direction and extend in the up-down direction. The longitudinal grooves  150  are arranged correspondingly to the spaces between the third guide ribs  131  (described later) of the inner slide cylinder  146  that are adjacent to each other in the circumferential direction. 
     Onto an upper end portion of the inner slide cylinder  146 , a lower end portion of the upper stem  139  is fitted so as to be freely slidable in the up-down direction. On a part of the inner slide cylinder  146  that is located between the upper end portion and the lower end portion (to be more specific, a connection part of the inner slide cylinder  146  that is connected to the connector plate  147 ), the third guide ribs  131  (guide ribs  125 ) are provided that protrude outwardly in the radial direction and extend along the up-down direction. Furthermore, the inner slide cylinder  146  is inserted into the insertion cylinder  122  of the ceiling wall portion  119  of the attachment cap  104 . A lower edge of the inner slide cylinder  146  is seated spaceably on the flange portion  140 . 
     Here, the third guide ribs  131  are provided on either one of the inner slide cylinder  146  and the ceiling wall portion  119  so as to be slidable with respect to the other. In the present embodiment, the third guide ribs  131  are formed on the inner slide cylinder  146  so as to be slidable in the up-down direction with respect to the insertion cylinder  122  of the ceiling wall portion  119 . Furthermore, above the third guide ribs  131 , a lower-end opening edge of the upper stem  139  is arranged so as to face the third guide ribs  131  with a gap therebetween. 
     Over the whole circumference, the connector plate  147  connects between the lower end portion of the inner slide cylinder  146  and a central section of the outer slide cylinder  145  along the up-down direction. The connector plate  147  is formed in an annular plate-like cylindrical shape or a cylindrical shape with a top whose diameter increases stepwise toward the lower direction. The inside of the cylinder for air  114  is divided into an upper chamber and a lower chamber by the connector plate  147 . Through the air hole  148  of the connector plate  147 , the upper chamber and the lower chamber are communicable with each other. 
     The air-liquid mixing chamber  115  mixes the content substance from the cylinder for liquid  112  with the air from the cylinder for air  114 . The air-liquid mixing chamber  115  is disposed in the stem  105 . In the example shown in the figure, the air-liquid mixing chamber  115  is located between the presser member  142  disposed in the upper end portion of the lower stem  138  and the vicinity of the reduced-diameter part  143  of the upper stem  139 . The air-liquid mixing chamber  115  is communicable with a lower chamber of the cylinder for air  114  through the insides of the longitudinal grooves  144 , through a gap between the inner slide cylinder  146  and the part of the lower stem  138  that corresponds to the piston for air, and through air introduction passages  152  for which the insides of the longitudinal grooves  150  are used. 
     The foaming member  116  is provided in the stem  105 . To be more specific, the foaming member  116  is fitted into an upper end portion of the upper stem  139 , and is mounted on the reduced-diameter part  143 . The foaming member  116  is made of a plurality of foaming elements  153  aligned in the up-down direction. The foaming element  153  is made of a cylindrical body in which a net body is stretched over an opening end edge of the cylindrical body. In the present embodiment, two foaming elements  153  are provided in the up-down direction. Of the two foaming elements  153 , the foaming element  153  on the upper side is provided with a net body only over an upper-end opening edge of the cylindrical body while the foaming element  153  on the lower side is provided with a net body only over a lower-end opening edge of the cylindrical body. 
     Note that the numbers of the foaming elements  153  and the net bodies may be at least one, respectively. Furthermore, with the net body of the foaming element  153  (fine mesh) located on the upper side and the net body of the foaming element  153  (rough mesh) located on the lower side being altered in the mesh size, it is possible to produce finer foam. 
     The air-liquid mixture obtained by mixing the content substance with the air mixed in the air-liquid mixing chamber  115  passes from the air-liquid mixing chamber  115  to the inside of the reduced-diameter part  143  and then circulates inside the foaming member  116 , to thereby be foamed into bubbles. 
     The depressing head  107  includes: a head main unit  154 ; and an exterior cylindrical portion  155 . The head main unit  154  and the exterior cylindrical portion  155  are formed as separate entities, and are fitted to each other. The head main unit  154  includes: a top wall portion  156 ; an attachment cylindrical portion  157 ; a fitting cylindrical portion  158 ; a covering wall portion  159 ; and a nozzle cylindrical portion  160 . 
     The top wall portion  156  is arranged above the stem  105 . 
     The attachment cylindrical portion  157  extends downwardly from the top wall portion  156  and is attached to the stem  105 . The attachment cylindrical portion  157  is arranged coaxially with the axis line O, and is fitted onto the upper end portion of the upper stem  139 . A lower end portion of the attachment cylindrical portion  157  is inserted into the guide cylindrical portion  120 . The attachment cylindrical portion  157  is freely movable in the guide cylindrical portion  120  in the up-down direction. 
     On an inner circumferential surface of an upper end portion of the attachment cylindrical portion  157 , restricting ribs  161  are provided that protrude inwardly in the radial direction. The restricting rib  161  is formed in a plate shape that extends in the up-down direction. Upper end portions of the restricting ribs  161  are connected to the top wall portion  156 . Lower end portions of the restricting ribs  161  are in contact with the upper end portion of the upper stem  139 . 
     The fitting cylindrical portion  158  protrudes downwardly from the top wall portion  156 , and is arranged coaxially with the axis line O. The fitting cylindrical portion  158  surrounds the upper end portion of the attachment cylindrical portion  157  from the outer side in the radial direction. 
     The nozzle cylindrical portion  160  extends from the attachment cylindrical portion  157  outwardly in the radial direction, and protrudes further outwardly in the radial direction than the fitting cylindrical portion  158 . The inside of the nozzle cylindrical portion  160  is in communication with the inside of the stem  105  through the inside of the upper end portion of the attachment cylindrical portion  157 . In a protrusion end of the nozzle cylindrical portion  160 , the discharge hole  106  is provided. Hereinafter, in the radial direction, a direction in which the nozzle cylindrical portion  160  extends is referred to as forward-rearward direction. A direction in which the discharge hole  106  opens along the forward-rearward direction (the right side in  FIG. 8 ) is referred to as forward direction while a direction opposite thereto (the left side in  FIG. 8 ) is referred to as rearward direction. 
     The covering wall portion  159  extends downwardly from an outer circumferential edge of the top wall portion  156 . The covering wall portion  159  is formed in a C shape that opens toward the forward direction in a planar view when the foamer dispenser  101  is seen in the up-down direction. A circumferential end portion of the covering wall portion  159  is connected to a side surface of the nozzle cylindrical portion  160  along the circumferential direction. The covering wall portion  159  covers the fitting cylindrical portion  158  and the upper end portion of the attachment cylindrical portion  157  from the outer side in the radial direction. 
     The exterior cylindrical portion  155  is provided at a position below the top wall portion  156 . An upper edge of the exterior cylindrical portion  155  is in contact with a lower surface of the top wall portion  156 . An upper end portion of the exterior cylindrical portion  155  is fitted into the fitting cylindrical portion  158 . In an upper end portion of the exterior cylindrical portion  155 , an annular protruded strip portion  162  is provided that protrudes outwardly in the radial direction. The protruded strip portion  162  is fitted (undercut-fitted or the like) to an inner circumferential surface of the fitting cylindrical portion  158 . 
     The exterior cylindrical portion  155  surrounds the attachment cylindrical portion  157  and the guide cylindrical portion  120  from the outer side in the radial direction. The inside of the exterior cylindrical portion  155  is communicable with the inside of the cylinder for air  114  through the inside of the guide cylindrical portion  120 . A lower end portion of the exterior cylindrical portion  155  is arranged at a position equivalent in the up-down direction to that of the lower end portion of the attachment cylindrical portion  157 . The lower end portion of the exterior cylindrical portion  155  surrounds the upper end portion of the guide cylindrical portion  120  from the outer side in the radial direction. 
     On the lower end portion of the exterior cylindrical portion  155 , an outer guide protrusion  163  is provided that protrudes inwardly in the radial direction. The outer guide protrusion  163  is formed in an annular shape. In a state before the depressing head  107  is depressed, the outer guide protrusion  163  faces the inner guide protrusion  123  in the radial direction and is close to the inner guide protrusion  123 . 
     In the upper end portion of the exterior cylindrical portion  155 , intake holes  164 ,  165  are formed. The intake holes  164 ,  165  penetrate through the exterior cylindrical portion  155  in the radial direction, and open toward the upward direction. Hereinafter, the intake hole  164  is referred to also as first intake hole  164  while the intake hole  165  is referred to also as second intake hole  165 . 
     Two first intake holes  164  are arranged in sections of the exterior cylindrical portion  155  that are located on both sides of the left-right direction, out of the radial directions, that is orthogonal to the forward-rearward direction. The two first intake holes  164  are formed so as to have equivalent shape and size. The first intake hole  164  is formed so as to have a rectangular shape in a side view when the foamer dispenser  101  is seen in the left-right direction. 
     Here, in opening circumferential edges of the intake holes  164 ,  165  in the outer circumferential surface of the exterior cylindrical portion  155 , receding sections  166  are formed that recede inwardly in the radial direction and are continuous to the intake holes  164 ,  165 . The receding section  166  is arranged in a part, of the opening circumferential edge of the first intake hole  164  in the outer circumferential surface of the exterior cylindrical portion  155 , that continues to the first intake hole  164  from below. The receding section  166  is formed in a rectangular shape when seen in a side view. The size of the receding section  166  in the circumferential direction is equivalent to that of the first intake hole  164  in the circumferential direction. 
     The first intake holes  164  are covered with the fitting cylindrical portion  158  and the covering wall portion  159  from the outer side in the radial direction. The first intake hole  164  is in communication with the outside of the foamer dispenser  101  through the receding section  166 . 
     The second intake hole  165  is located on the forward side in the exterior cylindrical portion  155 . The second intake hole  165  is arranged so that the position of the second intake hole  165  in the circumferential direction coincides with that of the nozzle cylindrical portion  160 . 
     Into the second intake hole  165 , the nozzle cylindrical portion  160  is inserted from above. The nozzle cylindrical portion  160  extends forwardly from the second intake hole  165  and protrudes further outwardly in the radial direction than the exterior cylindrical portion  155 . A size of the second intake hole  165  in the circumferential direction is equivalent to that of the nozzle cylindrical portion  160  in the circumferential direction. A side surface of the nozzle cylindrical portion  160  is locked between parts of an inner circumferential edge of the second intake hole  165  that face inwardly in the circumferential direction. 
     The second intake hole  165  is larger than the nozzle cylindrical portion  160  in the up-down direction. Therefore, between a lower surface of the nozzle cylindrical portion  160  and a part of the inner circumferential edge of the second intake hole  165  that faces upwardly, a gap is provided in the up-down direction. 
     On an inner circumferential surface of the exterior cylindrical portion  155 , guide ribs  167 ,  168  are protrudingly provided that extend in the up-down direction. 
     When the depressing head  107  is depressed obliquely, the guide ribs  167 ,  168  are capable of slidably contacting the guide cylindrical portion  120  (the inner guide protrusion  123  of the guide cylindrical portion  120 , in the example shown in the figure) from the outer side in the radial direction. The guide ribs  167 ,  168  are arranged in sections of the exterior cylindrical portion  155  that are opposite to each other in the radial direction across the guide cylindrical portion  120 . Hereinafter, the guide rib  167  is referred to also as first guide rib  167  while the guide rib  168  referred to also as second guide rib  168 . 
     The first guide ribs  167  are arranged on a forward section of the exterior cylindrical portion  155 . To be more specific, the first guide ribs  167  are arranged in a section beneath the second intake hole  165 . Upper end portions of the first guide ribs  167  are located beneath the inner circumferential edge of the second intake hole  165 . Lower end portions of the first guide ribs  167  are connected to the outer guide protrusion  163 . The first guide ribs  167  extend straightly in the up-down direction, and are connected smoothly to a surface of the outer guide protrusion  163 . 
     Although not specifically illustrated, three first guide ribs  167  are spaced in the circumferential direction in the forward section of the exterior cylindrical portion  155 . The three first guide ribs  167  are arranged at regular intervals in the circumferential direction. Of the three first guide ribs  167 , the one positioned in the middle in the circumferential direction is arranged right in the forward direction with respect to the axis line O. 
     The second guide ribs  168  are arranged in a rear section, which is a section located on a side opposite to the first guide ribs  167  in the radial direction. The second guide rib  168  is formed over the whole length of the rear section of the exterior cylindrical portion  155  in the up-down direction. Lower end portions of the second guide ribs  168  are connected to the outer guide protrusion  163 . The second guide ribs  168  extend straightly in the up-down direction, and are connected smoothly to a surface of the outer guide protrusion  163 . 
     Although not specifically illustrated, two second guide ribs  168  are spaced in the circumferential direction in the rear section of the exterior cylindrical portion  155 . The two second guide ribs  168  are arranged to avoid a part of the exterior cylindrical portion  155  that is located right in the rear direction with respect to the axis line O. 
     On the top wall portion  156  of the head main unit  154 , pairs of lock portions  169  are provided that protrude downwardly and are spaced from each other in the circumferential direction. The pairs of lock portions  169  are each locked between parts of an inner circumferential edge of each of the intake holes  164 ,  165  that face inwardly in the circumferential direction. 
     The pairs of lock portions  169  are each provided in each of the two first intake holes  164 , and are arranged in parts of the top wall portion  156  that are located on both sides in the left-right direction. The lock portion  169  is formed in a plate shape that extends in the radial direction. The lock portion  169  extends straightly along the left-right direction when seen in a planar view. Surfaces of the paired lock portions  169  that face in the circumferential direction are locked in the inner circumferential edge of the first intake hole  164 , and are close to or in contact with the inner circumferential edge. 
     The lock portion  169  connects between the attachment cylindrical portion  157  and the fitting cylindrical portion  158 . To be more specific, an end section of the lock portion  169  on the inner side in the radial direction is connected to the attachment cylindrical portion  157  while an end section thereof on the outer side in the radial direction is connected to the fitting cylindrical portion  158 . 
     Although not specifically illustrated, the size of the lock portion  169  in the up-down direction is smaller in a stepwise manner from the inner side to the outer side in the radial direction. Of the lock portion  169 , an in-cylinder portion, which is located inner in the radial direction than the exterior cylindrical portion  155  in the radial direction, protrudes further downwardly than a part that is located outer in the radial direction than the in-cylinder portion and that is arranged in the first intake hole  164 . The in-cylinder portion supports the exterior cylindrical portion  155  from the inner side in the radial direction. The in-cylinder portion is close to or in contact with the inner circumferential surface of the exterior cylindrical portion  155  from the inner side in the radial direction. 
     The top wall portion  156  is provided with a plurality of support plate portions  170  that protrude downwardly and extend in the radial direction. The support plate portions  170  are arranged in the circumferential direction. The support plate portions  170  are provided radially about the axis line O when seen in a planar view, and are arranged at intervals over the whole length in the circumferential direction. The support plate portions  170  are arranged at positions that avoid, in the circumferential direction, the nozzle cylindrical portion  160  and a section between each pair of lock portions  169 . 
     End sections of the support plate portions  170  on the inner side in the radial direction are connected to the attachment cylindrical portion  157 . End sections of the support plate portions  170  on the outer side in the radial direction support the exterior cylindrical portion  155  from the inner side in the radial direction, and are close to or in contact with the inner circumferential surface of the exterior cylindrical portion  155  from the inner side in the radial direction. The support plate portions  170  are spaced in the circumferential direction, to thereby constitute a plate portion train. The exterior cylindrical portion  155  is fitted onto the plate portion train. 
     In the foamer dispenser  101  with the structure as described above, when the depressing head  107  is depressed to move the stem  105  downwardly, the content substance in the container main unit  102  is transferred and mixed with air to form an air-liquid mixture, which is foamed to be in a bubble form and is then discharged from the discharge hole  106 . 
     In using the discharge vessel  110 , the restricting member  124  is detached from the attachment cap  104 , and then the depressing head  107  is depressed with respect to the container main unit  102 . Thereby, the stem  105  and the piston for liquid  111  are depressed in a unified manner. 
     At this time, the inner slide cylinder  146  of the piston for air  113  relatively moves on the external side of the part of the lower stem  138  that corresponds to the piston for air, and the upper end portion of the inner slide cylinder  146  slides on the inner circumferential surface of the upper stem  139 . Therefore, the position of the piston for air  113  in the up-down direction is maintained. As a result, between the flange portion  140  of the lower stem  138  and the lower edge of the inner slide cylinder  146  of the piston for air  113 , a communication gap is provided that communicates between the air introduction passage  152  and the lower chamber of the cylinder for air  114 . Thereby, the lower chamber and the air-liquid mixing chamber  115  are brought into communication with each other. Furthermore, at this time, the valve member  135  is also moved downwardly. Then, the lower valve body  137  of the valve member  135  is seated on the tapered cylindrical portion  127  of the cylinder for liquid  112 , to thereby close the lower opening section of the cylinder for liquid  112 . 
     When the depressing head  107  is depressed until the lower edge of the upper stem  139  is brought into contact with the third guide ribs  131  of the inner slide cylinder  146  of the piston for air  113 , the piston for air  113  is moved downwardly together with the depressing head  107 , and the outer slide cylinder  145  of the piston for air  113  slides downwardly on the inner circumferential surface of the circumferential wall of the cylinder for air  114 . 
     At this time, the valve body  149 , which is in contact with the connector plate  147  of the piston for air  113  from below, remains in close contact with the lower surface of the connector plate  147 , and hence, the air hole  148  is closed. As a result, air in the lower chamber of the cylinder for air  114  is compressed, and the air is transferred to the air-liquid mixing chamber  115  through the communication gap and the air introduction passage  152 . Furthermore, at this time, in a state with the lower opening section of the cylinder for liquid  112  being closed, the piston for liquid  111  is moved downwardly while the biasing member  134  is being compressed to deform, to thereby space the upper valve body  136  of the valve member  135  away from the valve seat portion (small-diameter section  130 ) of the piston for liquid  111 . This brings the inside of the cylinder for liquid  112  and the inside of the upper section of the lower stem  138  into communication with each other. Then, the content substance in the cylinder for liquid  112  flows through the inner side of the valve seat portion and the outer side of the upper valve body  136 , and presses up the liquid discharge valve  151 . Then, through the inner side of the valve seat  141 , the content substance is transferred to the air-liquid mixing chamber  115 . 
     As described above, with the depressing head  107  being depressed, the air and the content substance are separately transferred to the air-liquid mixing chamber  115 , where they are joined together and mixed. The obtained air-liquid mixture is transferred to the foaming member  116 , and passes through the mesh body of the lower foaming element  153  and the mesh body of the upper foaming element  153  in this order. This foams the air-liquid mixture into a bubble form, which flows through the nozzle cylindrical portion  160  and is discharged from the discharge hole  106 . 
     After that, when the depressing of the depressing head  107  is released, the piston for liquid  111  is pressed upwardly by the elastic restoring force of the biasing member  134 . As a result, the valve seat portion of the piston for liquid  111  is brought into contact with the upper valve body  136  of the valve member  135 , to thereby close the upper valve body  136 . This stops the transfer of the content substance to the air-liquid mixing chamber  115 . Furthermore, the lower valve body  137  is detached from the lower opening section of the cylinder for liquid  112 . As a result, the inside of the container main unit  102  and the inside of the cylinder for liquid  112  are brought into communication with each other, and the content substance in the container main unit  102  flows into the cylinder for liquid  112 . At this time, the inside of the container main unit  102  has a negative pressure. Therefore, through an introduction hole provided in a part of the cylinder for air  114  that is located above the outer slide cylinder  145 , the air in the upper chamber of the cylinder for air  114  that is located above the piston for air  113  is introduced into the container main unit  102 . 
     Furthermore, together with the piston for liquid  111  that rises as described above, the stem  105  and the depressing head  107  rise in a unified manner, to thereby bring the flange portion  140  of the lower stem  138  into contact with the lower edge of the inner slide cylinder  146  of the piston for air  113 . This blocks the communication between the lower chamber of the cylinder for air  114  and the air-liquid mixing chamber  115  through the air introduction passage  152 , to thereby stop the transfer of the air to the air-liquid mixing chamber  115 . After that, with the piston for air  113  being pressed up by the elastic restoring force of the biasing member  134 , the inside of the lower chamber has a negative pressure. This elastically deforms the valve body  149  of the piston for air  113  in the downward direction, to thereby open the air hole  148 . As a result, through the air hole  148 , the upper chamber of the cylinder for air  114 , the inside of the guide cylindrical portion  120 , and the inside of the exterior cylindrical portion  155 , outside air is supplied from the outside of the container into the lower chamber of the cylinder for air  114 . 
     According to the foamer dispenser  101  of the present embodiment as described above, either one of the outer circumferential surface of the insertion section of the discharge device  108  that is inserted into the guide portion  118  of the attachment cap  104  (to be more specific, the attachment cylindrical portion  157 , the lower portion of the upper stem  139 , and the inner slide cylinder  146  of the piston for air  113 ) and the inner circumferential surface of the guide portion  118  of the attachment cap  104  (to be more specific, the guide cylindrical portion  120 , and the insertion cylinder  122  of the ceiling wall portion  119 ) is provided with the guide ribs  125  that are slidable in the up-down direction with respect to the other. Therefore, remarkable effects as follows will be produced. 
     Even if, when the depressing head  107  is depressed, the discharge device  108  does not move straightly toward the downward direction but is to move in a direction that crosses the up-down direction, the guide ribs  125  provided on one of the two move in the up-down direction while sliding on the circumferential surface of the other. As a result, it is possible to inhibit the discharge device  108  from being depressed obliquely forwardly or rearwardly instead of straightly downwardly and from shaking with respect to the attachment cap  104 . 
     From above, when the depressing head  107  is depressed, it is possible to inhibit the oblique depressing or shaking (hereinafter, referred to shortly as shaking or the like) of the discharge device  108  with respect to the attachment cap  104 , and hence, to stabilize the positional relationship between the discharge device  108  and the attachment cap  104  in the radial direction. This stabilizes the operation of depressing. Therefore, operability of the foamer dispenser  101  is enhanced. 
     As guide ribs  125 , either one of the inner slide cylinder  146  of the piston for air  113  and the ceiling wall portion  119  of the attachment cap  104  is provided with the third guide ribs  131  that are slidable in the up-down direction with respect to the other. Therefore, shaking or the like when the piston for air  113  of the discharge device  108  is moved in the up-down direction with respect to the ceiling wall portion  119  of the attachment cap  104  is inhibited. Consequently, the aforementioned effect is further enhanced. 
     Furthermore, in the ceiling wall portion  19  of the attachment cap  104 , the insertion cylinder  122  into which the inner slide cylinder  146  of the piston for air  113  is inserted is provided. Therefore, it is possible to obtain a length along the up-down direction that is sufficiently long to allow the insertion cylinder  122  and the inner slide cylinder  146  to contact each other. Consequently, the aforementioned effect of inhibiting shaking or the like of the discharge device  108  is further enhanced. 
     Furthermore, in the present embodiment, the third guide ribs  131  are provided on the inner slide cylinder  146  of the piston for air  113 . Here, through the inner slide cylinder  146  of the piston for air  113 , the stem  105  is inserted. The inner slide cylinder  146  together with the stem  105  is inserted into the ceiling wall portion  119  of the attachment cap  104 . In the case of this structure, it is possible to obtain a more sufficient length of the third guide rib  131  along the up-down direction. Consequently, the aforementioned effect of inhibiting shaking or the like of the discharge device  108  is still further enhanced. 
     Furthermore, as guide ribs  125 , the fourth guide ribs  132 , which are slidable in the up-down direction with respect to the other, are provided with either one of the attachment cylindrical portion  157  of the depressing head  107  and the guide cylindrical portion  120  of the attachment cap  104 . Therefore, shaking or the like when the depressing head  107  of the discharge device  108  is moved in the up-down direction with respect to the guide cylindrical portion  120  of the attachment cap  104  is inhibited. Consequently, the aforementioned effect is still further enhanced. 
     Furthermore, in this case, the third guide rib  131  and the fourth guide rib  132  are allowed to be located in different sections along the up-down direction (allowed to be spaced in the up-down direction). Therefore, it is possible to inhibit the aforementioned shaking or the like of the discharge device  108  especially remarkably. 
     Furthermore, the inner circumferential surface of the exterior cylindrical portion  155  is protrudingly provided with the guide ribs  167 ,  168 . Therefore, for example, when the depressing head  107  is depressed obliquely, it is possible to make the guide cylindrical portion  120  slidable in the up-down direction on the guide ribs  167 ,  168 , and the guide cylindrical portion  120  makes it possible to restrict the displacement of the exterior cylindrical portion  155  in the radial direction. As a result, it is possible to stabilize the position of the exterior cylindrical portion  155  in the radial direction, and hence, to inhibit the wobbling of the depressing head  107  with respect to the attachment cap  104 . Furthermore, it is possible to stabilize the positional relationship between the exterior cylindrical portion  155  and the head main unit  154  in the radial direction. Therefore, even if the head main unit  154  and the exterior cylindrical portion  155  are formed as separate entities, it is possible to secure the operability of the foamer dispenser  101 . 
     Furthermore, the guide ribs  167 ,  168  are located in the sections of the exterior cylindrical portion  155  that are opposite to each other in the radial direction across the guide cylindrical portion  120 . Therefore, when the depressing head  107  is depressed obliquely, it is possible to bring the guide ribs  167 ,  168  into slidable contact with the guide cylindrical portion  120  from both outer sides in the radial direction, and hence, to further stabilize the position of the exterior cylindrical portion  155  in the radial direction. 
     Furthermore, the first guide rib  167  and the second guide rib  168  are arranged in the sections of the exterior cylindrical portion  155  that are located on both sides in the forward-rearward direction. Therefore, when the depressing head  107  is depressed obliquely, the first guide rib  167  and the second guide rib  168  make it possible to stabilize the position of the exterior cylindrical portion  155  in the forward-rearward direction. Accordingly, even if, when the depressing head  107  is depressed, a front end of the nozzle cylindrical portion  160  is depressed to produce an external force that may incline the depressing head  107  in the forward direction, it is possible to effectively inhibit the wobbling of the depressing head  107  with respect to the attachment cap  104 , and also to securely stabilize the positional relationship between the exterior cylindrical portion  155  and the head main unit  154  in the forward-rearward direction. 
     Furthermore, because the intake holes  164 ,  165  are formed in the upper end portion of the exterior cylindrical portion  155 , the following effects are obtained. 
     In a foamer dispenser in which the exterior cylindrical portion  155  is not provided with the intake holes  164 ,  165  as is the conventional case, when the depressing head  107  moves back upwardly, outside air is sucked into the exterior cylindrical portion  155  through the gap between the inner circumferential surface of the exterior cylindrical portion  155  and the outer circumferential surface of the guide cylindrical portion  120  (hereinafter, referred to as “cylinder-cylinder gap”), and is then drawn into the cylinder for air  114  through the inside of the guide cylindrical portion  120 . Here, if foreign matter such as water is attached to the outer surface of the attachment cap  104 , there is a possibility that, when the depressing head  107  moves back upwardly, the foreign matter together with the air is sucked into the exterior cylindrical portion  155  through the cylinder-cylinder gap and intrudes into the cylinder for air  114 . 
     On the other hand, in the foamer dispenser  101  of the present embodiment, the intake holes  164 ,  165  are formed in the upper end portion of the exterior cylindrical portion  155 . Therefore, when the depressing of the depressing head  107  is released to cause the inside of the cylinder for air  114  to have a negative pressure, it is possible to suck the outer air into the exterior cylindrical portion  155  through the intake holes  164 ,  165 . As a result, sucking of outside air into the exterior cylindrical portion  155  through the cylinder-cylinder gap is inhibited, and hence, sucking of foreign matter together with the outside air into the exterior cylindrical portion  155  through the cylinder-cylinder gap is inhibited. Therefore, it is possible to inhibit the intrusion of foreign matter into the cylinder for air  114 . 
     Furthermore, because the intake holes  164 ,  165  are formed in the upper end portion of the exterior cylindrical portion  155 , it is possible to maintain a low influence that the intake holes  164 ,  165  have on the appearance of the depressing head  107 . 
     Furthermore, the intake holes  164 ,  165  open toward the upward direction. Therefore, for example when the exterior cylindrical portion  155  is molded with a mold, it is possible to remove the mold with ease, and hence, to make it easy to form the foamer dispenser  101  with simplicity. 
     Furthermore, on the opening circumferential edges of the intake holes  164 ,  165  in the outer circumferential surface of the exterior cylindrical portion  155 , the receding sections  166  are formed. Therefore, foreign matter such as water is unlikely to intrude. Furthermore, it is possible to introduce the outside air into the intake holes  164 ,  165  through the receding sections  166 , and hence, to effectively suck the outside air into the exterior cylindrical portion  155 . 
     Furthermore, the head main unit  154  is provided with the covering wall portion  159 . Therefore, it is possible to inhibit the intake holes  164 ,  165  from being exposed to the outside, and hence, to maintain the appearance of the foamer dispenser  101  favorable. 
     Furthermore, the top wall portion  156  is provided with the pairs of lock portions  169 . Therefore, when the head main unit  154  and the exterior cylindrical portion  155  are to rotate relatively in the circumferential direction, the paired lock portions  169  are locked in the inner circumferential edges of the intake holes  164 ,  165 , to thereby make it possible to restrict the rotation. Furthermore, when the exterior cylindrical portion  155  is to be deformed so as to narrow the intake holes  164 ,  165  in the circumferential direction, the paired lock portions  169  are locked in the inner circumferential edges of the intake holes  164 ,  165 , to thereby make it possible to restrict the deformation as well. 
     Furthermore, the pairs of lock portions  169  are spaced in the circumferential direction. Therefore, it is possible to securely communicate between the outer portion and inner portion of the exterior cylindrical portion  155  through the sections of the intake holes  164 ,  165  that are located between the pairs of lock portions  169 , while the rotation and deformation as described above are being restricted. Consequently, it is possible to securely suck the outside air into the exterior cylindrical portion  155  through the intake holes  164 ,  165 . 
     In the present embodiment, the top wall portion  156  is provided with the fitting cylindrical portion  158  which protrudes downwardly and onto which the attachment cylindrical portion  157  is fitted, and lock portions  169  connect between the attachment cylindrical portion  157  and the fitting cylindrical portion  158 . In this case, when the paired lock portions  169  are locked in the inner circumferential edges of the intake holes  164 ,  165 , it is possible to support both ends of the lock portions  169  in the radial direction by the attachment cylindrical portion  157  and the fitting cylindrical portion  158 , and hence, to effectively restrict the rotation and the deformation. 
     Furthermore, on the top wall portion  156 , the support plate portions  170  are arranged. The inner ends of the support plate portions  170  in the radial direction are connected to the attachment cylindrical portion  157  while the outer ends of the support plate portions  170  support the exterior cylindrical portion  155  from the inner side in the radial direction. Therefore, for example, when the exterior cylindrical portion  155  is to shake in the radial direction with respect to the head main unit  154 , it is possible to cause the top wall portion  156  and the attachment cylindrical portion  157  to support the exterior cylindrical portion  155  via the support plate portions  170 . As a result, it is possible to attach the exterior cylindrical portion  155  tightly to the head main unit  154 , and hence, for example, to inhibit shaking between the exterior cylindrical portion  155  and the head main unit  154 . 
     Furthermore, the top wall portion  156  is provided with the fitting cylindrical portion  158 . Therefore, it is possible to sandwich the exterior cylindrical portion  155  between the fitting cylindrical portion  158  and the support plate portions  170  in the radial direction, and hence, to attach the exterior cylindrical portion  155  further tightly to the head main unit  154 . 
     Furthermore, the in-cylinder portions of the lock portions  169  that are located on the inner side in the radial direction than the exterior cylindrical portion  155  support the exterior cylindrical portion  155  from the inner side in the radial direction. Therefore, it is possible to support the exterior cylindrical portion  155  from the inner side in the radial direction not only by the support plate portions  170  but also by the in-cylinder portions of the lock portions  169 , and hence, to attach the exterior cylindrical portion  155  further tightly to the head main unit  154 . 
     The present invention is not limited to the aforementioned embodiment, and various modifications can be made without departing from the spirit or scope of the present invention. 
     For example, in the aforementioned embodiment, the third guide ribs  131  are formed on the inner slide cylinder  146  so as to be slidable in the up-down direction with respect to the insertion cylinder  122  of the ceiling wall portion  119 . However, the present invention is not limited to this. The third guide ribs  131  may be formed on the insertion cylinder  122  so as to be slidable in the up-down direction with respect to the inner slide cylinder  146 . 
     Furthermore, the fourth guide ribs  132  are formed on the guide cylindrical portion  120  so as to be slidable in the up-down direction with respect to the attachment cylindrical portion  157 . However, the present invention is not limited to this. The fourth guide ribs  132  may be formed on the attachment cylindrical portion  157  so as to be slidable in the up-down direction with respect to the guide cylindrical portion  120 . 
     Furthermore, the guide ribs  125  may be formed on the lower portion of the upper stem  139  so as to be slidable in the up-down direction with respect to the guide portion  118 . 
     The restricting member  124  may be not provided. 
     In the aforementioned embodiment, the first guide rib  167  and the second guide rib  168  are provided. However, the present invention is not limited to this. For example, guide ribs may be arranged on the sections of the inner circumferential surface of the exterior cylindrical portion  155  that are located on both sides in the left-right direction. 
     Furthermore, the guide ribs  167 ,  168  may not be arranged on the sections of the exterior cylindrical portion  155  that are opposite to each other in the radial direction across the guide cylindrical portion  120 . In addition, the guide ribs  167 ,  168  may not be provided. 
     Furthermore, the in-cylinder portions of the lock portions  169  may not support the exterior cylindrical portion  155  from the inner side in the radial direction. In addition, the lock portions  169  may not connect between the attachment cylindrical portion  157  and the fitting cylindrical portion  158 . Furthermore, the lock portion  169  may not be provided. 
     Furthermore, the nozzle cylindrical portion  160 , the fitting cylindrical portion  158 , and the covering wall portion  159  may not be provided. 
     In this case, for example, the discharge hole  106  may be formed of a through-hole that penetrates through the exterior cylindrical portion  155 . Furthermore, the support plate portions  170  may not be provided. 
     Furthermore, the receding sections  166  may not be provided. 
     Furthermore, in the aforementioned embodiment, the first intake holes  164  and the second intake hole  165  are provided. However, the present invention is not limited to this. For example, as intake hole(s), at least either the first intake holes or the second intake hole may be provided. 
     Furthermore, the intake holes  164 ,  165  may not be provided. 
     Otherwise, it is appropriately possible to replace the constituent elements of the embodiments with known constituent elements without departing from the spirit or scope of the present invention. Furthermore, the aforementioned modifications may be appropriately combined. 
     For example, in the foamer dispenser  10  according to the first embodiment, either one of the inner slide cylinder  32  and the ceiling wall portion  16  may be provided with a third guide rib that is slidable in the up-down direction with respect to the other. Furthermore, either one of the attachment cylindrical portion  44  and the guide cylindrical portion  17  may be provided with a fourth guide rib that is slidable in the up-down direction with respect to the other. 
     INDUSTRIAL APPLICABILITY 
     According to the present invention, it is possible to provide a foamer dispenser that is capable of inhibiting the intrusion of foreign matter such as water into the cylinder for air. 
     Furthermore, according to the present invention, it is possible to provide a foamer dispenser in which the exterior cylindrical portion can be attached tightly to the head main unit. 
     Furthermore, according to the present invention, it is possible to provide a foamer dispenser in which oblique depressing of the depressing head can be restricted to stabilize the positional relationship between the exterior cylindrical portion and the head main unit in the radial direction. 
     Furthermore, it is possible to provide a foamer dispenser in which, when the depressing head is depressed, the discharge device can be inhibited from being obliquely depressed or from shaking with respect to the attachment cap. 
     REFERENCE SIGNS LIST 
       1 : container main unit 
       1   a : mouth portion 
       10 : foamer dispenser 
       11 : attachment cap 
       12 : stem 
       13 : discharge device 
       14 : nozzle hole 
       15 : depressing head 
       16 : ceiling wall portion 
       17 : guide cylindrical portion 
       25 : piston for liquid 
       26 : cylinder for liquid 
       27 : piston for air 
       28 : cylinder for air 
       29 : air-liquid mixing chamber 
       30 : foaming member 
       41 : head main unit 
       42 : exterior cylindrical portion 
       43 : top wall portion 
       44 : attachment cylindrical portion 
       45 : fitting cylindrical portion 
       46 : covering wall portion 
       47 : nozzle cylindrical portion 
       51   a : first intake hole 
       51   b : second intake hole 
       52 : receding section 
       53   a : first guide rib 
       53   b : second guide rib 
       54 : lock portion 
       54   a : in-cylinder portion 
       55 : support plate portion 
       101 : foamer dispenser 
       102 : container main unit 
       103 : mouth portion 
       104 : attachment cap 
       105 : stem 
       106 : discharge hole 
       107 : depressing head 
       108 : discharge device 
       111 : piston for liquid 
       112 : cylinder for liquid 
       113 : piston for air 
       114 : cylinder for air 
       115 : air-liquid mixing chamber 
       116 : foaming member 
       118 : guide portion 
       119 : ceiling wall portion 
       120 : guide cylindrical portion 
       122 : insertion cylinder 
       125 : guide rib 
       131 : third guide rib 
       132 : fourth guide rib 
       146 : inner slide cylinder 
       156 : top wall portion 
       157 : attachment cylindrical portion