Patent Publication Number: US-2021161536-A1

Title: Ligation device

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation application of International Application No. PCT/JP2019/027544, filed Jul. 11, 2019, which claims priority to International Application No. PCT/JP2018/026229, filed Jul. 11, 2018. The contents of these applications are incorporated herein by reference in their entirety. 
    
    
     BACKGROUND 
     The disclosed embodiments relate to a ligation device. 
     A ligation device for ligating an affected area such as a diverticula and a varix formed in a patient&#39;s digestive tract or the like is known. Such a ligation device is disclosed in JPH07-59786. With a ligation kit disclosed in JPH07-59786, a slide cylinder is driven by a fluid, and an O-ring attached on an inner cylinder is pushed out and ejected from the inner cylinder by the slide cylinder to ligate an affected area. 
     However, with the ligation kit according to JPH07-59786, the O-ring stretched and attached to the inner cylinder is pushed out by the fluid-driven slide cylinder to eject the O-ring from the inner cylinder. Thus, the O-ring falls under an endoscopic visual field, and when searching another affected area, a good visual field cannot be secured. 
     SUMMARY 
     An object of the disclosed embodiments is to provide a ligation device that can always secure a good endoscopic visual field. 
     In order to achieve this object, a ligation device according to a disclosed embodiment includes a cylindrical inner cylinder having a distal end portion, a slider having a cylindrical shape, attached around the inner cylinder, movable with respect to the inner cylinder along an axial direction of the inner cylinder, and having an annular groove extending along a circumferential direction on an inner peripheral face of the slider, and a ligation ring attached around the inner cylinder and located in the annular groove. The inner cylinder may be located on, e.g., a distal end portion of an endoscope. The distal end portion of the inner cylinder may project toward the distal end side of a distal end face of the endoscope. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a sectional view of a ligation device of the disclosed embodiments attached to an endoscope, illustrating a state that a slider is located on a proximal end side, and 
         FIG. 1B  is a sectional view of the ligation device attached to the endoscope, illustrating a state that the slider in  FIG. 1A  is advanced; 
         FIG. 2A  is a front view of one slider piece, 
         FIG. 2B  is a plan view of one slider piece, 
         FIG. 2C  is a side view of one slider piece, 
         FIG. 2D  is a front view of the other slider piece, 
         FIG. 2E  is a plan view of the other slider piece, and 
         FIG. 2F  is a side view of the other slider piece; 
         FIG. 3A  is a sectional view of a ligation device of the disclosed embodiments attached to an endoscope, illustrating a state that a slider is located on a proximal end side, and 
         FIG. 3B  is a sectional view of the ligation device attached to the endoscope, illustrating a state that the slider in  FIG. 3A  is advanced; 
         FIG. 4  is a partially cut-out sectional view of a ligation device of the disclosed embodiments including an endoscope portion; 
         FIG. 5A  is a front view of a slider of a ligation device of the disclosed embodiments, and 
         FIG. 5B  is a diagram illustrating a state that the slider in  FIG. 5A  is divided; 
         FIG. 6  is a diagram illustrating a state that a part of an outer periphery of a ligation ring is temporarily fixed to a bottom face of an annular groove using an adhesive; 
         FIG. 7  is an enlarged sectional view of a tapered portion of an inner cylinder in  FIG. 5A ; 
         FIG. 8A  is a sectional view of a ligation device of the disclosed embodiments attached to an endoscope, illustrating a state that a slider is located on a proximal end side, and 
         FIG. 8B  is a sectional view of the ligation device attached to the endoscope, illustrating a state that the slider in  FIG. 8A  is advanced; 
         FIG. 9A  is a sectional view of a ligation device of the disclosed embodiments attached to an endoscope, illustrating a state that a slider is located on a proximal end side, and 
         FIG. 9B  is a sectional view of the ligation device attached to the endoscope, illustrating a state that the slider in  FIG. 9A  is advanced; 
         FIG. 10  is a sectional view of a ligation device of the disclosed embodiments attached to an endoscope, illustrating a state that a slider is located on a proximal end side; 
         FIG. 11A  is a partial sectional view of a ligation device of the disclosed embodiments attached to an endoscope, illustrating a state that a slider is located on a proximal end side, and 
         FIG. 11B  is a partial sectional view taken along line XIb-XIb in  FIG. 11A ; 
         FIG. 12A  and  FIG. 12B  are diagrams explaining operations of the ligation device in  FIG. 11A ; 
         FIG. 13A  is a partial sectional view of a ligation device of the disclosed embodiments attached to an endoscope, illustrating a state that a slider is located on a proximal end side, and 
         FIG. 13B  is a partial sectional view taken along line XIIIb-XIIIb in  FIG. 13A ; 
         FIG. 14A  is a partial sectional view of a ligation device of the disclosed embodiments attached to an endoscope, illustrating a state that a slider is located on a proximal end side, and 
         FIG. 14B  is a partial sectional view taken along line XIVb-XIVb in  FIG. 14A ; 
         FIG. 15  is a diagram illustrating a state that an inner cylinder in  FIG. 13A  and the slider in  FIG. 14A  are combined; 
         FIG. 16A  is a partial sectional view of the ligation device of the disclosed embodiments attached to the endoscope, illustrating a state that the slider is located on the proximal end side, 
         FIG. 16B  is a partial sectional view of the ligation device of the disclosed embodiments attached to the endoscope, illustrating a state that the slider is located on the proximal end side, and 
         FIG. 16C  is a partial sectional view of the ligation device of the disclosed embodiments attached to the endoscope, illustrating a state that the slider is located on the proximal end side; 
         FIG. 17A  is a partial sectional view of a ligation device of the disclosed embodiments attached to an endoscope, illustrating a state that a slider is located on a proximal end side, and 
         FIG. 17B  is a partial sectional view taken along line XVIIb-XVIIb in  FIG. 17A ; 
         FIG. 18A  and  FIG. 18B  are diagrams explaining operations of the ligation device in  FIG. 17A ; 
         FIG. 19A  is a partial sectional view of a ligation device of the disclosed embodiments attached to an endoscope, illustrating a state that a slider is located on a proximal end side, and 
         FIG. 19B  is a partial sectional view taken along line XIXb-XIXb in  FIG. 19A ; 
         FIG. 20A  is a partial sectional view of a ligation device of the disclosed embodiments attached to an endoscope, illustrating a state that a slider is located on a proximal end side, and 
         FIG. 20B  is a partial sectional view taken along line XXb-XXb in  FIG. 20A ; 
         FIG. 21  is a diagram illustrating a state that the slider in  FIG. 19A  and an outer cylinder in  FIG. 20A  are combined; 
         FIG. 22A  is a partial sectional view of the ligation device of the disclosed embodiments attached to the endoscope, illustrating a state that the slider is located on the proximal end side, 
         FIG. 22B  is a partial sectional view of the ligation device of the disclosed embodiments attached to the endoscope, illustrating a state that the slider is located on the proximal end side, and 
         FIG. 22C  is a partial sectional view of the ligation device of the disclosed embodiments attached to the endoscope, illustrating a state that the slider is located on the proximal end side; 
         FIG. 23A  is a sectional view of a ligation device of the disclosed embodiments attached to an endoscope, illustrating a state that a slider is located on a proximal end side, and 
         FIG. 23B  is a sectional view taken along line XXIIIb-XXIIIb in  FIG. 23A ; and 
         FIG. 24A  is a sectional view of a ligation device of the disclosed embodiments attached to an endoscope, illustrating a state that a slider is located on a proximal end side, and 
         FIG. 24B  is a sectional view taken along line XXIVb-XXIVb in  FIG. 24A . 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, the disclosed embodiments will be explained with reference to the figures. Note that sizes of the ligation device illustrated in the figures are described to make it easier to understand the contents of the embodiments, and do not correspond to the actual sizes. 
     A ligation device  1  will be explained with reference to the figures. 
       FIG. 1A  is a sectional view of a ligation device  1  attached to an endoscope  2 , illustrating a state that a slider  40  is located on a proximal end side.  FIG. 1B  is a sectional view of the ligation device  1  attached to the endoscope  2 , illustrating a state that the slider  40  is advanced.  FIG. 1A  and  FIG. 1B  illustrate only a distal end portion of the endoscope  2  equipped with the ligation device  1 . Note that, for the slider  40 , only a slider piece  45  is illustrated (see  FIG. 2 ), and for the endoscope  2 , its appearance is illustrated, and a sectional view of the endoscope  2  is not illustrated (the same applies to the following figures). 
     Additionally, in  FIG. 1A  and  FIG. 1B , the left side of the figure is a distal end side (farther side) to be inserted into a body, and the right side is a proximal end side (hand side, nearer side). The endoscope  2  has a forceps hole  2   a  through which forceps not illustrated are inserted. 
     The ligation device  1  includes a joining member  10 , an inner cylinder  20 , an outer cylinder  30 , the slider  40 , a sealing member  50 , ligation rings  60 ,  61  and  62 , and a tube  70 . 
     The joining member  10  has a hollow cylindrical shape and is placed for fixing the ligation device  1  to the endoscope  2 , and pressure-joined to an outer periphery of the endoscope  2 . An annular groove  11  is formed on a distal inner periphery of the joining member  10 . A material constituting the joining member  10  is not particularly limited as long as the material has a strength for fixing the ligation device  1  to the endoscope  2  for preventing the ligation device from separating from the endoscope  2 , and is biocompatible. For example, elastic materials such as a natural rubber, a synthetic rubber, and a thermoplastic elastomer can be used. Examples of the synthetic rubber include an isoprene rubber, a butadiene rubber, a styrene-butadiene rubber, a nitrile rubber, a butyl rubber, an ethylene-propylene rubber, an acrylic rubber, a fluorine rubber, a silicone rubber, and the like. In addition, examples of the thermoplastic elastomer include a styrene-based elastomer, an olefin-based elastomer, a polyester-based elastomer, a polyurethane-based elastomer, a polyamide-based elastomer, and the like. 
     The inner cylinder  20  is connected to a distal end portion of the joining member  10 , and located on an endoscope distal end portion  2   b , and attached to the endoscope distal end portion  2   b  in an airtight state or liquid-tight state. The inner cylinder  20  includes a proximal end portion  21 , an intermediate portion  22 , and a distal end portion  23 . The proximal end portion  21  is configured so as to be thinner than the intermediate portion  22  and have an outer diameter smaller than of the intermediate portion  22 . On an outer periphery of the proximal end portion  21 , an annular protruding portion  24  projecting outward is placed. The protruding portion  24  is fitted into the annular groove  11  of the joining member  10 , so that the inner cylinder  20  is fixed to the joining member  10 . 
     The intermediate portion  22  is located on the distal end side of the proximal end portion  21 . On an inner peripheral face  25  of the intermediate portion  22 , an annular projection  26  that projects inward is placed. A distal end of the endoscope distal end portion  2   b  abut on the projection  26  in an axial direction. 
     The distal end portion  23  is located on the distal end side of the intermediate portion  22 . The distal end portion  23  projects toward the distal end side of a distal end face  2   c  of the endoscope  2 . The distal end-side portion of the distal end portion  23  has a tapered portion  27  whose outer diameter gradually decreases toward the distal end. The distal end portion  23  and the distal end face  2   c  of the endoscope  2  constitute a recessed space  28 . 
     A material constituting components such as the inner cylinder  20  is not particularly limited, and a metal material, a resin material, and a ceramic material can be used. Typical examples of the metal material include a stainless steel, titanium, and a nickel-titanium alloy. Examples of the resin material include a polyethylene, a polypropylene, a polyvinyl chloride, a polystyrene, an acrylic resin, a phenolic resin, a melamine resin, a polyimide, a polyamide, a polycarbonate, a polyether sulfone, a polyetheretherketone, and a polytetrafluoroethylene. Examples of the ceramic material include glass and fine ceramics. 
     Since the ligation rings  60 ,  61  and  62  are attached to the inner cylinder  20  as described later, typical examples of the material constituting the inner cylinder  20  are not particularly limited as long as the material has a strength enough to withstand the ligation rings  60 ,  61  and  62  and is biocompatible. The material constituting the inner cylinder  20  may be a translucent material, e.g. a polypropylene, a polycarbonate, a polyethersulfone, a polyimide, or an acrylic resin, for maintaining a wide visual field during treatment. Incidentally, the material constituting the inner cylinder  20  need not be a translucent material. 
     The outer cylinder  30  includes an outer cylindrical portion  31  placed around the intermediate portion  22  of the inner cylinder  20 , and an outer cylinder cap  32 . The inner cylinder  20  and the outer cylinder  30  constitute a slide space  29 . 
     An annular protruding portion  33  projecting inward is placed on the distal end of the outer cylindrical portion  31 . The protruding portion  33  and the intermediate portion  22  constitute an annular opening  34  where the slide space  29  is open. The outer cylinder cap  32  is bonded to the proximal end of the outer cylindrical portion  31  using an adhesive. An inner peripheral end of the outer cylinder cap  32  is fitted into a groove  12  composed of the proximal end of the intermediate portion  22  and the distal end of the joining member  10 , so that movement of the outer cylinder  30  in the axial direction is restricted. The outer cylinder cap  32  closes the proximal end side of the slide space  29 . A through-hole  35  communicating with the slide space  29  is formed on the outer cylinder cap  32 . In the axial direction, the distal end of the outer cylindrical portion  31  is disposed at almost the same position as the projection  26  of the inner cylinder  20 . 
     A material constituting the outer cylinder  30  is not particularly limited as long as the material has a strength against the pressure of the fluid and is biocompatible as described later, and for example, the materials cited as the material for the inner cylinder  20  can be used. In addition, a material for the adhesive is not particularly limited as long as the material has a strength against the pressure of the fluid and is biocompatible, and examples of the material include an acrylic resin-based adhesive, a urethane resin-based adhesive, an epoxy resin-based adhesive, a vinyl chloride resin solvent-based adhesive, a cyanoacrylate-based adhesive, a silicone-based adhesive, a phenol resin-based adhesive, and the like. 
     The slider  40  is cylindrical, placed between the inner cylinder  20  and the outer cylinder  30 , and movably (e.g. reciprocably) attached around the inner cylinder  20  in an airtight or liquid-tight state. On the distal end portion and/or proximal end portion of the slider  40 , a gap between the slider  40  and the inner cylinder  20  is made smaller than thicknesses of the ligation rings  60 ,  61  and  62 . An axial-direction length of the slider  40  is made substantially equal to the length of the outer cylindrical portion  31  of the outer cylinder  30 . 
     The slider  40  includes a cylindrical portion  41  and a flange portion  42 . On an inner peripheral face  43  of the cylindrical portion  41 , three annular grooves  44   a ,  44   b  and  44   c  are formed at a predetermined interval along the axial direction. The annular grooves  44   a ,  44   b  and  44   c  are configured to have dimensions capable of accommodating the ligation rings  60 ,  61  and  62  described later. As illustrated in  FIG. 1A  and  FIG. 1B , when the slider  40  reciprocates with respect to the inner cylinder  20 , the annular grooves  44   a ,  44   b  and  44   c  of the slider  40  advance and retract from the slide space  29  to the tapered portion  27 . In a state that the slider  40  is located on the most distal end side, the flange portion  42  abuts on the protruding portion  33 , and the slider  40  is prevented from coming out from the slide space  29 . Incidentally, the slider  40  may be configured only to be able to advance with respect to the inner cylinder  20 . 
     In addition, as illustrated in  FIG. 2A ,  FIG. 2B ,  FIG. 2C ,  FIG. 2D ,  FIG. 2E , and  FIG. 2F , the slider  40  is composed of a plurality of (two in the ligation device  1 ) slider pieces  45  and  46  divided together with the annular grooves  44   a ,  44   b  and  44   c  along a plane including an axis c of the slider  40 . In the ligation device  1 , the slider  40  is composed of two slider pieces  45  and  46  obtained by half-cutting a hollow cylinder along the plane including the axis of the slider  40 . Each of the slider pieces  45  and  46  includes half-cylindrical portions  45   a  and  46   a  corresponding to the cylindrical portion  41 , and half-flange portions  45   b  and  46   b  corresponding to the flange portion  42 , respectively. Each of the half-cylindrical portions  45   a  and  46   a  has half-annular grooves  45   d   1 ,  45   d   2 ,  45   d   3 ,  46   d   1 ,  46   d   2  and  46   d   3  corresponding to the annular grooves  44   a ,  44   b  and  44   c . In addition, a pair of fitting recessed portions  45   c  are formed on a half-cut face of the half-cylindrical portion  45   a , and a pair of fitting protruding portions  46   c  are formed on the half-cylindrical portion  46   a . The pair of fitting protruding portions  46   c  are fitted into the pair of fitting recessed portions  45   c , and they are bonded to each other using an adhesive, so that the slider pieces  45  and  46  are integrated to form the slider  40 . 
     A material constituting the slider  40  is not particularly limited as long as the material has excellent slidability to the inner cylinder  20  and is biocompatible, and the materials cited as the materials for the inner cylinder  20  can be used. The material constituting the slider  40  may be a translucent material, e.g. a polypropylene, a polycarbonate, a polyethersulfone, a polyimide, an acrylic resin, or the like for maintaining a wide visual field during treatment. Incidentally, the material constituting the slider  40  need not be a translucent material. In addition, a material for the adhesive is not particularly limited as long as the material has a strength against the pressure of the fluid and is biocompatible, and examples of the material include an acrylic resin-based adhesive, a urethane resin-based adhesive, an epoxy resin-based adhesive, a vinyl chloride resin solvent-based adhesive, a cyanoacrylate-based adhesive, a silicone-based adhesive, a phenol resin-based adhesive, and the like. 
     The sealing member  50  has an annular shape and is placed so as to be slidable in the slide space  29  while abutting on the inner periphery of the outer cylinder cap  32  and the outer periphery of the inner cylinder  20 . This sealing member  50  is fixed to the proximal end of the slider  40  so as to be movable together with the slider  40 . Thereby a space surrounded by the sealing member  50 , the outer cylinder cap  32 , the inner cylinder  20 , and the outer cylindrical portion  31  is airtightly preserved. The material constituting the sealing member  50  is not particularly limited as long as the material can preserve the space in the airtight state and is biocompatible. For example, elastic materials such as a natural rubber, a synthetic rubber, and a thermoplastic elastomer can be used. Examples of the synthetic rubber include an isoprene rubber, a butadiene rubber, a styrene-butadiene rubber, a nitrile rubber, a butyl rubber, an ethylene-propylene rubber, an acrylic rubber, a fluorine rubber, a silicone rubber, and the like. In addition, examples of the thermoplastic elastomer include a styrene-based elastomer, an olefin-based elastomer, a polyester-based elastomer, a polyurethane-based elastomer, a polyamide-based elastomer, and the like. 
     The ligation rings  60 ,  61  and  62  are O-rings, which are attached to the outer periphery of the inner cylinder  20  and located inside the annular grooves  44   a ,  44   b  and  44   c . When the slider  40  is disposed at a position opposite to the side of the distal end portion  23  of the inner cylinder  20  (most proximal end side), the ligation rings  60 ,  61  and  62  are disposed at a position opposite to the side of the distal end portion  23  of the inner cylinder  20  with respect to the projection  26 . A material constituting the ligation rings  60 ,  61  and  62  is not particularly limited as long as the material sufficiently extends so as to be attachable to the inner cylinder  20  and has a ligation force sufficient to necrotize an affected area, and is biocompatible. For example, elastic materials such as a natural rubber, a synthetic rubber, and a thermoplastic elastomer can be used. Examples of the synthetic rubber include an isoprene rubber, a butadiene rubber, a styrene-butadiene rubber, a nitrile rubber, a butyl rubber, an ethylene-propylene rubber, an acrylic rubber, a fluorine rubber, a silicone rubber, and the like. In addition, examples of the thermoplastic elastomer include a styrene-based elastomer, an olefin-based elastomer, a polyester-based elastomer, a polyurethane-based elastomer, a polyamide-based elastomer, and the like. Incidentally, the materials constituting the ligation rings  60 ,  61  and  62  may include e.g. a radiopaque material such as gold, platinum, tungsten, an alloy containing these elements (e.g. a platinum-nickel alloy, or the like), barium sulfate, bismuth subcarbonate, bismuth trioxide, bismuth oxychloride, and bismuth subcarbonate, or a powder of the radiopaque material. Sectional shapes of the ligation rings  60 ,  61  and  62  are not limited to circle, and may be another shape such as rectangle. A color of the ligation rings  60 ,  61  and  62  is preferably a color such as black, which is distinct from a surrounding tissue. 
     The tube  70  extends from the distal end portion to the proximal end portion along the endoscope  2 . A syringe, not illustrated, for delivering the fluid such as air to the slider  40  is connected to the proximal end of the tube  70 . The distal end of the tube  70  is airtightly connected to the proximal end of the through-hole  35  of the outer cylinder cap  32 . The material constituting the tube  70  is not particularly limited as long as the material has flexibility capable of following deformation of the endoscope  2  and is biocompatible, and examples of the material include a polyethylene, a polypropylene, a polyvinyl chloride, a fluororesin, and the like. 
     As illustrated in  FIG. 1A , the tapered portion  27  is configured to have a length L 1  larger than a distance L 2  from the distal end of the slider  40  to a proximal end of the annular groove  44   c  on the most proximal end side. In addition, the tapered portion  27  is configured such that a difference L 3  between a proximal outer diameter and a distal outer diameter of a slope  27   a  is larger than a difference between the outer diameter and the inner diameter of the ligation rings  60 ,  61  and  62 . Herein, the outer diameters and inner diameters of the ligation rings  60 ,  61  and  62  mean the outer diameters and inner diameters in a state that the ligation rings  60 ,  61  and  62  are attached around the inner cylinder  20 . 
     A whole length of the ligation device  1  (length from the distal end of the inner cylinder  20  to the proximal end of the joining member  10 ) may be set to e.g. 20 to 25 mm. In an inner cylinder  20  (part without the projection  26 ), for example, an inner diameter may be set to 8 to 16 mm, and an outer diameter (maximum diameter) may be set to 11 to 25 mm. 
     Next, an example of how to use the ligation device  1  will be explained. Herein, a method of ligating a diverticula formed on a wall face of a digestive tract will be explained as an example. 
     First, as illustrated in  FIG. 1A , in a state that the whole slider  40  is located on the slide space  29 , the endoscope  2  equipped with the ligation device  1  is inserted into the digestive tract, and an inside of the digestive tract is observed. A bleeding diverticula is identified, the endoscope  2  and the ligation device  1  are made close to the diverticula, the diverticula is sucked through the forceps hole  2   a , the diverticula is reversed so as to protrude toward the endoscope  2 , and the diverticula is located in the recessed space  28 . As illustrated in  FIG. 1B , a fluid is delivered to the slide space  29  through the tube  70  by operating the syringe not illustrated, and the slider  40  and the sealing member  50  are advanced using a pressure of the fluid as a driving source. The slider  40  moves to the distal end side of the inner cylinder  20 , and the ligation ring  60  located on the most distal end moves to the tapered portion  27 . Thereby, the ligation ring  60  moves to the distal end side on the tapered portion  27  while the diameter of the ligation ring  60  gradually decreases, and the ligation ring  60  is ejected from the tapered portion  27 , and the sucked diverticula is ligated by the ligation ring  60 . Then, the endoscope  2  equipped with the ligation device  1  is taken out of the digestive tract. After that, the ligated diverticula necrotizes and is discharged to the outside of the body together with the ligation ring  60 . 
     The ligation device  1  is configured such that the ligation rings  60 ,  61  and  62  are located in the annular grooves  44   a ,  44   b  and  44   c  of the slider  40 , and the slider  40  can reciprocate along the axial direction of the inner cylinder  20 . Thereby, if the slider  40  and the ligation rings  60 ,  61  and  62  are advanced in an attempt to ligate an affected area but the ligation is aborted, the slider  40  can be retracted together with the ligation rings  60 ,  61  and  62 . Thus, when moving the endoscope  2  to another affected area, the slider  40  and the ligation rings  60 ,  61  and  62  can be removed from a visual field of the endoscope  2 , so that a good visual field can be secured. In addition, when ligating another affected area, an advancement amount of the slider can be accurately adjusted (the slider can be accurately advanced to a predetermined position) by retracting the slider  40  to a predetermined position, e.g. a position illustrated in  FIG. 1A . In addition, when ligating another affected area, new ligation can be performed by advancing the slider  40 . 
     Since the slider  40  is composed of the plurality of slider pieces  45  and  46  divided together with the annular grooves  44   a ,  44   b  and  44   c , the slider  40  can be formed around the inner cylinder  20  such that the ligation rings  60 ,  61  and  62  can be fitted within the annular grooves  44   a ,  44   b  and  44   c  on the inner cylinder  20  equipped with the ligation rings  60 ,  61  and  62 . 
     Since the slider  40  is divided into the plurality of slider pieces  45  and  46  along a plane including the axis of the slider  40 , the slider  40  can be easily placed around the inner cylinder  20  such that the ligation rings  60 ,  61  and  62  can be fitted within the annular grooves  44   a ,  44   b  and  44   c  on the inner cylinder  20  equipped with the ligation rings  60 ,  61  and  62 . In addition, the slider  40  can be easily prepared. 
     The distal end portion  23  of the inner cylinder  20  includes the tapered portion  27  whose outer diameter gradually decreases toward the distal end, and therefore, when the slider  40  moves to the distal end side of the inner cylinder  20  and the ligation rings  60 ,  61  and  62  move to the tapered portion  27 , the ligation rings  60 ,  61  and  62  move to the distal end side of the distal end portion  23  on the tapered portion  27  while diameters of the ligation rings  60 ,  61  and  62  gradually decrease, and the ligation rings are ejected from the distal end portion  23 , so that the affected area can be ligated. 
     Since the tapered portion is configured to have the length L 1  larger than the distance L 2  from the distal end of the slider  40  to the proximal end of the annular groove  44   c  on the most proximal end side, all of the ligation rings  60 ,  61  and  62  can move to the distal end side of the inner cylinder  20  along the tapered portion  27  while the diameters of the ligation rings gradually decrease before the distal end of the slider  40  projects toward the distal end side with respect to the distal end of the inner cylinder  20 , so that the affected area can be securely ligated. 
     Since the tapered portion  27  is configured such that the difference L 3  between the proximal outer diameter and the distal outer diameter of the slope  27   a  is larger than the difference between the outer diameter and the inner diameter of the ligation rings  60 ,  61  and  62 , the ligation rings  60 ,  61  and  62  can be securely ejected on the tapered portion  27 . 
     The plurality of annular grooves  44   a ,  44   b  and  44   c  are formed on the inner peripheral face  43  of the slider  40 , and the plurality of ligation rings  60 ,  61  and  62  are attached to an outer peripheral face  20 A of the inner cylinder  20  such that the ligation rings  60 ,  61  and  62  correspond to the plurality of annular grooves  44   a ,  44   b  and  44   c  respectively. Thus, ligation can be continuously performed without taking the ligation device  1  out of the body. In addition, when ligation of the first affected area is completed and the endoscope  2  is moved to another affected area, the slider  40  and the ligation rings  61  and  62  can be removed from the visual field of the endoscope  2  by retracting the slider  40  together with the ligation rings  61  and  62 , so that a good visual field can be secured. In addition, when ligating another affected area, the slider  40  is advanced again, so that ligation can be performed by the ligation rings  61  and  62 . 
     Since the inner cylinder  20  is attached to the endoscope distal end portion  2   b  in an airtight or liquid-tight state, a force enough to suck the affected area into the recessed space  28  composed of the distal end portion  23  of the inner cylinder  20  and the endoscope distal end portion  2   b  can be generated. 
     On the distal end portion and/or the proximal end portion of the slider  40 , the gap between the slider  40  and the inner cylinder  20  is configured to be smaller than the thicknesses of the ligation rings  60 ,  61  and  62 , and therefore the ligation rings  60 ,  61  and  62  can be securely moved together with the slider  40 , so that the affected area can be securely ligated. 
     Since the inner peripheral face  25  of the inner cylinder  20  has the projection  26  on which the distal end of the endoscope distal end portion  2   b  abuts, the projection  26  makes it easier to position the ligation device  1  with respect to the endoscope distal end portion  2   b.    
     The inner cylinder  20  and/or the slider  40  is made of a translucent material, so that a wide visual field during treatment using the endoscope  2  can be maintained. 
     A ligation device  101  will be explained with reference to the figures. 
       FIG. 3A  is a sectional view of the ligation device  101  of the disclosed embodiments attached to the endoscope  2 , illustrating a state that the slider  40  is located on the proximal end side.  FIG. 3B  is a sectional view of the ligation device  101  attached to the endoscope  2 , illustrating a state that the slider  40  is advanced.  FIG. 3A  and  FIG. 3B  illustrate only the distal end portion of the endoscope  2  equipped with the ligation device  101 . 
     Additionally, in  FIG. 3A  and  FIG. 3B , the left side of the figure is a distal end side (farther side) to be inserted into a body, and the right side is a proximal end side (hand side, nearer side). The endoscope  2  has a forceps hole  2   a  through which forceps not illustrated are inserted. 
     Note that, in this explanation of the ligation device  101 , the same members as in the ligation device  1  are given the same reference numerals as in the ligation device  1 , and detailed explanation of the same members is not repeated. 
     The ligation device  101  includes the joining member  10 , an inner cylinder  120 , the outer cylinder  30 , the slider  40 , the sealing member  50 , the ligation rings  60 ,  61  and  62 , and the tube  70 . 
     As illustrated in  FIG. 3A  and  FIG. 3B , in the inner cylinder  120  of the ligation device  101 , the distal end portion  123  has no tapered portion. That means, the distal end portion  123  is configured to have a thickness that is substantially constant from the proximal end to the distal end of the inner cylinder  120 . In this configuration, as illustrated in  FIG. 3B , when the ligation rings  60 ,  61  and  62  are ejected from the distal end portion  123  of the inner cylinder  120 , the annular grooves  44   a ,  44   b  and  44   c  are located closer to the distal end side than the distal end of the distal end portion  123  of the inner cylinder  120 . That means the distal end portion of the slider  40  projects closer to the distal end side than the distal end of the distal end portion  123  of the inner cylinder  120 . Thereby, the slider  40 , the inner cylinder  120 , and the endoscope distal end portion  2   b  constitute a large recessed space  47 . 
     In addition, since the slider  40  is attached around the inner cylinder  120  in an airtight or liquid-tight state, a force enough to suck an affected area into the recessed space  47  composed of the slider  40 , the inner cylinder  120  and the endoscope distal end portion  2   b  can be generated even in a state that the slider  40  is located on the distal end side of the inner cylinder  120 . Furthermore, a larger volume of affected area can be contained in the recessed space  47 . 
     A ligation device  201  will be explained with reference to the figures. 
       FIG. 4  is a partially cut-out sectional view of a ligation device  201  of the disclosed embodiments, including the endoscope portion  2 .  FIG. 4  illustrates only a distal end portion of the ligation device  201  including an endoscope portion  2 . 
     Additionally, in  FIG. 4 , the left side of the figure is a distal end side (farther side) to be inserted into a body, and the right side is a proximal end side (hand side, nearer side). 
     Note that, in this explanation of the ligation device  201 , the same members as in the ligation device  1  are given the same reference numerals as in the ligation device  1 , and detailed explanation of the same members is not repeated. 
     The ligation device  201  includes an inner cylinder  220 , the endoscope portion  2 , the outer cylinder  30 , the slider  40 , the sealing member  50 , the ligation rings  60 ,  61  and  62 , and the tube  70 . 
     The inner cylinder  220  is located on the endoscope distal end portion  2   b  and is formed integrally with the endoscope distal end portion  2   b . The inner cylinder  220  includes a proximal end portion  221 , an intermediate portion  222 , and a distal end portion  223 . The intermediate portion  222  is located on the distal end side of the proximal end portion  221 . The inner peripheral end of the outer cylinder cap  32  is fitted into a groove  212  between the intermediate portion  222  and the proximal end portion  221 . 
     The distal end portion  223  is located on the distal end side of the intermediate portion  222 . The distal end portion  223  projects toward the distal end side of the distal end face  2   c  of the endoscope portion  2 . The distal end-side portion of the distal end portion  223  has a tapered portion  227  whose outer diameter gradually decreases toward the distal end. The distal end portion  223  and the distal end face  2   c  of the endoscope  2  constitute a recessed space  228 . A configuration such as a length of the tapered portion  227  may be the same as of the tapered portion  27  in the ligation device  1 . 
     The ligation device  201  having such a configuration can also exhibit the same effect as of the ligation device  1 . 
     Although the disclosed embodiments have been described above, the present disclosure is not limited to the aforementioned embodiments and can be variously modified. 
     For example, in the aforementioned embodiments, although the slider  40  is composed of two slider pieces  45  and  46  obtained by cutting a hollow cylinder into half along the plane including the axis c of the slider  40 , a slider  140  may be divided into a plurality of (two in this modification example) hollow cylindrical slider pieces  145  and  146  along a plane perpendicular to the axis c of the slider  140 , as illustrated in  FIG. 5A  and  FIG. 5B . The position for the division may face the annular groove. 
     The slider piece  145  has an annular notch  145   a  and a pair of fitting recessed portions  145   b  on the right side of a left figure of  FIG. 5B . The slider piece  146  has a pair of fitting protruding portions  146   c  on the left side of a right figure of  FIG. 5B . The pair of fitting protruding portions  146   c  are fitted into the pair of fitting recessed portions  145   b , and they are bonded to each other using an adhesive, so that the slider pieces  145  and  146  are integrated, the annular groove  144  is formed, and the slider  140  having a cylindrical portion  141  and a flange  142  is formed. Incidentally, although the sliders  40  and  140  are divided into two pieces in the aforementioned embodiments and modification examples, the sliders  40  and  140  may be divided into three or more pieces. 
     In addition, as illustrated in  FIG. 6 , a ligation ring  63  having a rectangular sectional shape is adopted instead of the ligation rings  60 ,  61  and  62 , and a part of an outer periphery of the ligation ring  63  may be temporarily fixed to a bottom face (inner peripheral face)  44   d  constituting the annular groove  44   a  using an adhesive  64 . Herein, an inner periphery of the ligation ring  63  may or may not come into contact with the outer peripheral face  20 A of the intermediate portion  22  of the inner cylinder  20 . 
     According to this configuration, a frictional resistance of the ligation ring  63  to the inner cylinder  20  decreases, and therefore the slider  40  can be smoothly moved. A material constituting the adhesive  64  is not particularly limited as long as the material has an adhesivity by which a part of the outer periphery of the ligation ring  63  is bonded to the bottom face (inner peripheral face)  44   d  of the annular groove  44   a  in a state that the ligation ring  63  is attached to the intermediate portion  22  of the inner cylinder  20 , and the part of the outer periphery of the ligation ring  63  leaves the bottom face (inner peripheral face)  44   d  of the annular groove  44   a  by a diameter-reducing force of the ligation ring  63  when the ligation ring  63  moves to the tapered portion  27 , and the material is biocompatible. Examples of the material include an acrylic resin-based adhesive, a urethane resin-based adhesive, an epoxy resin-based adhesive, a vinyl chloride resin solvent-based adhesive, a cyanoacrylate-based adhesive, a silicone-based adhesive, a phenolic resin-based adhesive, and the like. 
     In addition, although three ligation rings  60 ,  61  and  62  are placed in the aforementioned embodiments, it is only necessary to place one or more ligation rings. In addition, although the fluid for driving the slider  40  is air in the aforementioned embodiments, the fluid may be a liquid such as physiological saline. Incidentally, as the ligation ring, for example, a ring-shaped member made of a shape-memory alloy can be used. When such a ring-shaped member is ejected from the annular groove of the slider, the shape of the ring-shaped member changes from circle to non-circle, and therefore ligation in accordance with a shape of the affected area is possible. Also, a clip made of a shape-memory alloy can be used as the ligation ring. When accommodated in the annular groove of the slider, such a clip is ring-shaped, and when ejected from the annular groove of the slider, the clip is transformed into a previously-memorized shape. 
     In addition, the aforementioned embodiments have a configuration that the outer cylinder  30  is placed around the inner cylinder  20  to form a slide space  29 , and the slider  40  is driven by a fluid, but a configuration that a hydraulic cylinder is placed instead of the outer cylinder  30  and the sealing member  50 , and the slider  40  is driven by the hydraulic cylinder may be adopted. 
     In addition, as illustrated in  FIG. 7 , a level difference portion  27   b  may be formed on the proximal end of the tapered portion  27 . Preferably, a radial-direction width of the level difference portion  27   b  is larger than the difference between the inner diameter and the outer diameter of the ligation rings  60 ,  61  and  62 . According to this configuration, when the ligation rings  60 ,  61  and  62  move to the level difference portion  27   b , the ligation rings  60 ,  61  and  62  decrease in diameter and leave the slider  40 , then the ligation rings  60 ,  61  and  62  move to the distal end side of the distal end portion  23  on the tapered portion  27  while the diameters of the ligation rings gradually decrease, and are ejected from the distal end portion  23 , so that the affected area can be ligated. If the level difference portion  27   b  is formed in such a way, it becomes easy to form a tapered portion having the length L 1  larger than the distance L 2  from the distal end of the slider  40  to the proximal end of the annular groove  11  on the most proximal end side, and the ligation rings  60 ,  61  and  62  can be ejected from the distal end portion  23  while the distal end of the slider  40  does not project toward the distal end side from the distal end of the inner cylinder  20 , so that the affected area can be securely ligated. 
       FIG. 8A  is a sectional view of a ligation device  301  of the disclosed embodiments attached to the endoscope  2 , illustrating a state that the slider  40  is located on the proximal end side.  FIG. 8B  is a sectional view of the ligation device  301  attached to the endoscope  2 , illustrating a state that the slider  40  is advanced.  FIG. 8A  and  FIG. 8B  illustrate only the distal end portion of the endoscope  2  equipped with the ligation device  301 . 
     Additionally, in  FIG. 8A  and  FIG. 8B , the left side of the figure is a distal end side (farther side) to be inserted into a body, and the right side is a proximal end side (hand side, nearer side). The endoscope  2  has the forceps hole  2   a  through which forceps not illustrated are inserted. 
     Note that, in this explanation of the ligation device  301 , the same members as in the ligation device  1  are given the same reference numerals as in the ligation device  1 , and detailed explanation of the same members is not repeated. 
     The ligation device  301  includes the joining member  10 , the inner cylinder  20 , the outer cylinder  30 , the slider  40 , the sealing member  50 , the ligation rings  60 ,  61  and  62 , and a rod  370 . 
     The rod  370  extends from the distal end portion to the proximal end portion along the endoscope  2 . The distal end of the rod  370  is inserted through the through-hole  35  of the outer cylinder cap  32  and connected to the sealing member  50 . The proximal end portion of the rod  370  can be operated by an operator. When the operator pushes and pulls the proximal end portion of the rod  370 , the slider  40  advances and retracts together with the sealing member  50 . 
     In the ligation device  301 , when the rod  370  is pushed, the slider  40  advances from the state illustrated in  FIG. 8A  and moves to the distal end side of the inner cylinder  20  as illustrated in  FIG. 8B . As a result, the ligation ring  60  located on the most distal end moves to the tapered portion  27 , the ligation ring  60  is ejected from the tapered portion  27 , and a sucked diverticula is ligated by the ligation ring  60 . Then, the rod  370  is pulled, so that the advanced slider  40  and the ligation rings  61  and  62  can be retracted to a predetermined position e.g. a position illustrated in  FIG. 8A . 
     The ligation device  301  having such a configuration can also exhibit the same effect as of the ligation device  1 . 
     Preferably, the material constituting the rod  370  has sufficient tensile strength and rigidity from the viewpoint of preventing the rod  370  itself from being cut and securely advancing and retracting the slider  40 . Examples of the material include a metal material such as a stainless steel like SUS304, a nickel-titanium alloy, and a cobalt-chromium alloy, and the like. Additionally, the sealing member  50  need not be provided, and the rod  370  may be directly connected to the proximal end of the slider  40 . 
       FIG. 9A  is a sectional view of a ligation device  401  of the disclosed embodiments attached to the endoscope  2 , illustrating a state that the slider  40  is located on the proximal end side.  FIG. 9B  is a sectional view of the ligation device  401  attached to the endoscope  2 , illustrating a state that the slider  40  is advanced.  FIG. 9A  and  FIG. 9B  illustrate only the distal end portion of the endoscope  2  equipped with the ligation device  401 . 
     Additionally, in  FIG. 9A  and  FIG. 9B , the left side of the figure is a distal end side (farther side) to be inserted into a body, and the right side is a proximal end side (hand side, nearer side). The endoscope  2  has the forceps hole  2   a  through which forceps not illustrated are inserted. 
     Note that, in this explanation of the ligation device  401 , the same members as in the ligation device  1  are given the same reference numerals as in the ligation device  1 , and detailed explanation of the same members is not repeated. 
     The ligation device  401  includes the joining member  10 , the inner cylinder  20 , an outer cylinder  430 , the slider  40 , the sealing member  50 , the ligation rings  60 ,  61  and  62 , a first wire  470 , and a second wire  471 . 
     The outer cylinder  430  includes an outer cylindrical portion  431  placed around the intermediate portion  22  and the distal end portion  23  of the inner cylinder  20 , and an outer cylinder cap  432 . The inner cylinder  20  and the outer cylinder  430  constitute a slide space  429 . 
     The distal end of the outer cylindrical portion  431  is disposed at almost the same position as the distal end of the inner cylinder  20  in the axial direction. On the distal end of the outer cylindrical portion  431 , an annular protruding portion  433  that projects inward is placed. The protruding portion  433  and the distal end portion  23  constitute an annular opening  434  through which a slide space  429  opens. The outer cylindrical portion  431  has a first through-hole  436  that penetrates from the distal end to the proximal end. 
     The outer cylinder cap  432  is bonded to the proximal end of the outer cylindrical portion  431  using an adhesive. An inner peripheral end of the outer cylinder cap  432  is fitted into the groove  12  composed of the proximal end of the intermediate portion  22  and the distal end of the joining member  10 , so that movement of the outer cylinder  430  in the axial direction is restricted. The outer cylinder cap  432  closes the proximal end side of the slide space  429 . The outer cylinder cap  432  has a second through-hole  435  and a third through-hole  437 . The third through-hole  437  is formed outside the second through-hole  435  and communicates with the proximal end of the first through-hole  436 . The second through-hole  435  communicates with the slide space  429 . 
     The first wire  470  extends from the distal end portion to the proximal end portion along the endoscope  2 . One end of the first wire  470  is connected to the distal end of the cylindrical portion  41  of the slider  40 . The first wire  470  extends from the portion connected to the cylindrical portion  41  toward the distal end side, passes through the opening  434 , turns back along the distal end of the outer cylindrical portion  431 , passes through the first through-hole  436  of the outer cylindrical portion  431  and the third through-hole  437  of the outer cylinder cap  432 , and extends to the proximal end portion of the endoscope  2 . The proximal end of the first wire  470  can be operated by an operator. When the wire  470  is pulled by the operator, the slider  40  is pulled and advanced. 
     The second wire  471  extends from the distal end portion to the proximal end portion along the endoscope  2 . The distal end of the second wire  471  is inserted through the second through-hole  435  of the outer cylinder cap  432  and connected to the sealing member  50 . The proximal end of the second wire  471  is configured to be operable by an operator. When the proximal end of the second wire  471  is pulled by the operator, the slider  40  is pulled together with the sealing member  50  and retracts. 
     In the ligation device  401 , when the first wire  470  is pulled, the slider  40  is pulled and advances from the state illustrated in  FIG. 9A , and moves to the distal end side of the inner cylinder  20  as illustrated in  FIG. 9B . As a result, the ligation ring  60  located on the most distal end moves to the tapered portion  27 , the ligation ring  60  is ejected from the tapered portion  27 , and a sucked diverticula is ligated by the ligation ring  60 . Then, the second wire  471  is pulled, so that the advanced slider  40  and the ligation rings  61  and  62  can be retracted to a predetermined position e.g. a position illustrated in  FIG. 9A . 
     The ligation device  401  having such a configuration can also exhibit the same effect as of the ligation device  1 . 
     As the first wire  470  and the second wire  471 , for example, a known wire or rope made of a metal material or a resin material can be used. Additionally, the sealing member  50  need not be provided, and the second wire  471  may be connected directly to the proximal end of the slider  40 . 
       FIG. 10  is a sectional view of a ligation device  501  attached to the endoscope  2 , illustrating a state that a slider  540  is located on a proximal end side.  FIG. 10  illustrates only the distal end portion of the endoscope  2  equipped with the ligation device  501 . 
     Additionally, in  FIG. 10 , the left side of the figure is a distal end side (farther side) to be inserted into a body, and the right side is a proximal end side (hand side, nearer side). The endoscope  2  has the forceps hole  2   a  through which forceps not illustrated are inserted. 
     Note that, in this explanation of the ligation device  501 , the same members as in the ligation device  1  are given the same reference numerals as in the ligation device  1 , and detailed explanation of the same members is not repeated. 
     The ligation device  501  includes the joining member  10 , the inner cylinder  20 , the outer cylinder  30 , the slider  540 , the sealing member  50 , ligation rings  60 ,  61  and  562 , and the tube  70 . 
     In the ligation device  501 , two annular grooves  44   a  and  44   b  are formed on the inner peripheral face  43  of the slider  540 , and the ligation rings  60  and  61  are attached to the outer peripheral face  20 A of the inner cylinder  20  such that the ligation rings  60  and  61  correspond to the annular grooves  44   a  and  44   b  respectively. In addition, as an additional ligation ring, the ligation ring  562  located on the distal end side of the distal end of the slider  540  and attached around the inner cylinder  20  is placed. On the distal end of the slider  540 , a slider extension portion  548  that projects toward the outer peripheral side of the ligation ring  562  is provided. When the slider  540  is disposed at a position opposite to the side of the distal end portion  23  of the inner cylinder  20  (most proximal end side), the additional ligation ring  562  is disposed at a position corresponding to the projection  26  in the axial direction. Additionally, in the axial direction, the ligation rings  60  and  61  are disposed at a position opposite to the side of the distal end portion  23  of the inner cylinder  20  with respect to the projection  26 . 
     In the ligation device  501 , when the number of the ligation rings is the same (unchanged), the ligation device  501  can decrease an axial-direction length of the slider  540 , and consequently a size of the ligation device  501  can be decreased. When the ligation device  501  is operated in vivo, an unnecessary force is not applied to the ligation ring  562  from another device or a human body tissue with the slider extension portion  548 , and failures such as erroneous ejection of the ligation ring  562  can be prevented. 
     The ligation device  501  having such a configuration can also exhibit the same effect as of the ligation device  1 . Incidentally, in this example, the slider  540  need not have the slider extension portion  548 . 
       FIG. 11A  is a partial sectional view of a ligation device  601  attached to the endoscope  2 , illustrating a state that a slider  640  is located on a proximal end side.  FIG. 11B  is a partial sectional view taken along line XIb-XIb in  FIG. 11A .  FIG. 11A  illustrates only a part of the distal end portion of the endoscope  2  equipped with the ligation device  601 . In  FIG. 11B , the endoscope  2  is omitted. 
     Additionally, in  FIG. 11A , the left side of the figure is a distal end side (farther side) to be inserted into a body, and the right side is a proximal end side (hand side, nearer side). The endoscope  2  has the forceps hole  2   a  through which forceps not illustrated are inserted. 
     Note that, in this explanation of the ligation device  601 , the same members as in the ligation device  1  are given the same reference numerals as in the ligation device  1 , and detailed explanation of the same members is not repeated. 
     The ligation device  601  includes the joining member  10 , an inner cylinder  620 , the outer cylinder  30 , a slider  640 , the sealing member  50 , the ligation rings  60 ,  61  and  62 , and the tube  70 . 
     In the inner peripheral face  43  of the slider  640 , a part of the proximal end side more proximal than the annular groove  44   c  has a larger diameter. An inner gap  620   b  is formed between the enlarged-diameter part of the inner peripheral face  43  of the slider  640  and the outer peripheral face  20 A of the inner cylinder  620 . 
     On the outer peripheral face  20 A of the inner cylinder  620 , a first projection  620 A projecting into the inner gap  620   b  is placed. On the inner peripheral face  43  of the slider  640 , a plurality of (three) second projections  640 A projecting into the inner gap  620   b  are placed along the axial direction. The plurality of second projections  640 A are located on the proximal end side of the first projection  620 A in a state that the slider  640  is located on the proximal end side. The first projection  620 A and each second projection  640 A have a saw-like sectional shape obtained by cutting the slider  640  along a plane including the axial direction of the slider  640 . Incidentally, the sectional shape of the projections may be a trapezoid, a chevron shape, and a cylindrical shape, or the like. The first projection  620 A and each second projection  640 A have a rectangular shape when viewed from the axial direction. The first projection  620 A and the plurality of second projections  640 A are arranged in a row along the axial direction. 
     The plurality of second projections  640 A are configured such that a distance between the second projections  640 A adjacent to each other is substantially equal to the distance between the ligation rings  60 ,  61  and  62  adjacent to each other. A distance between the first projection  620 A and the second projection  640 A located on the most distal end side is set to a distance at which the ligation ring  60  is ejected from the slider  640  when the slider  640  advances and the second projection  640 A located on the most distal end side crosses over the first projection  620 A. 
     A sum of heights of the first projection  620 A and each second projection  640 A in the radial direction of the slider  640  is structurally larger than a radial-direction width of the inner gap  620   b  (distance between the inner peripheral face  43  of the part with the enlarged diameter and the outer peripheral face  20 A). That means, as illustrated in  FIG. 11B , the first projection  620 A and each second projection  640 A share a part where they overlap each other when the ligation device  601  is viewed from the distal end side. 
     As illustrated in  FIG. 11A , a radial-direction height of one of the plurality of second projections  640 A is structurally different from radial-direction heights of the other remaining second projections  640 A. In the ligation device  601 , the plurality of second projections  640 A are configured such that their radial-direction heights gradually increase toward the proximal end side in the axial direction. The heights of the plurality of second projections may be equal to each other. 
       FIG. 12A  and  FIG. 12B ) are diagrams explaining operations of the ligation device  601 . 
     A fluid is delivered to the slide space  29  through the tube  70  by operating a syringe not illustrated, and the slider  640  and the sealing member  50  are advanced using a pressure of the fluid as a driving source. As illustrated in  FIG. 12A , the second projection  640 A located on the most distal end side is made to abut on the first projection  620 A. When the driving force of the fluid for moving the slider  640  exceeds a predetermined magnitude, the second projection  640 A crosses over the first projection  620 A and moves to the distal end side, as illustrated in  FIG. 12B . At this time, the ligation ring  60  is ejected from the slider  640 , moves to the distal end side on the tapered portion  27  while the diameter of the ligation ring  60  gradually decreases, and then the ligation ring  60  is ejected from the tapered portion  27 . Furthermore, when the second projection  640 A located in the middle in the axial direction crosses over the first projection  620 A by advancing the slider  640 , the ligation ring  61  is ejected from the slider  640 , and when the second projection  640 A located on the most proximal end side crosses over the first projection  620 A, the ligation ring  62  is ejected from the slider  640 . 
     The ligation device  601  is configured such that a sum of heights of the first projection  620 A and each second projection  640 A in the radial direction of the slider  640  is larger than a radial-direction width of the inner gap  620   b . Thus, for example when the second projection  640 A crosses over the first projection  620 A by advancing the slider  640 , the ligation ring  60  is ejected from the slider  640 , and this configuration makes it possible to eject the ligation ring  60  at an intended timing. 
     Since the plurality of second projections  640 A are placed along the axial direction, the plurality of ligation rings  60 ,  61  and  62  can be sequentially ejected at an intended timing. A radial-direction height of one of the plurality of second projections  640 A is structurally different from radial-direction heights of the other remaining second projections  640 A. Thereby, a driving force for moving the slider  640  in ejecting the ligation rings  60 ,  61  and  62  can be changed. 
     The plurality of second projections  640 A are configured such that their radial-direction heights gradually increase toward the proximal end side in the axial direction. Thus, for example, it is possible to prevent an event that, after the second projection  640 A located on the most distal end side crosses over the first projection  620 A and the ligation ring  60  is ejected, the slider  640  advances, the second projection  640 A located in the middle crosses over the first projection  620 A, and the ligation ring  61  is erroneously ejected. 
     Furthermore, the ligation device  601  having such a configuration can also exhibit the same effect as of the ligation device  1 . 
       FIG. 13A  is a partial sectional view of a ligation device  701  attached to the endoscope  2 , illustrating a state that a slider  740  is located on a proximal end side.  FIG. 13B  is a partial sectional view taken along line XIIIb-XIIIb in  FIG. 13A .  FIG. 13A  illustrates only a part of the distal end portion of the endoscope  2  equipped with the ligation device  701 . In  FIG. 13B , the endoscope  2  is omitted. 
     Additionally, in  FIG. 13B , the left side of the figure is a distal end side (farther side) to be inserted into a body, and the right side is a proximal end side (hand side, nearer side). The endoscope  2  has the forceps hole  2   a  through which forceps not illustrated are inserted. 
     Note that, in this explanation of the ligation device  701  the same members as in the ligation device  1  are given the same reference numerals as in the ligation device  1 , and detailed explanation of the same members is not repeated. 
     The ligation device  701  includes the joining member  10 , an inner cylinder  720 , the outer cylinder  30 , a slider  740 , the sealing member  50 , the ligation rings  60 ,  61  and  62 , and the tube  70 . 
     In the inner peripheral face  43  of the slider  740 , a part of the proximal end side more proximal than the annular groove  44   c  has a larger diameter. An inner gap  720   b  is formed between the enlarged-diameter part of the inner peripheral face  43  of the slider  740  and the outer peripheral face  20 A of the inner cylinder  720 . 
     On the outer peripheral face  20 A of the inner cylinder  720 , a first groove  720   c  extending along the axial direction is formed. On a bottom portion of the first groove  720   c , a first projection  720 A projecting into the inner gap  720   b  is placed. On the inner peripheral face  43  of the slider  740 , a plurality of second projections  740 A projecting into the inner gap  720   b  are placed along the axial direction. Configurations and positional relationships of the first projection  720 A and the plurality of second projections  740 A are almost the same as those of the first projection  620 A and the plurality of second projections  640 A in the ligation device  601 . A top portion of each second projection  740 A is accommodated in the first groove  720   c . That means, a height of each second projection  740 A is larger than a radial-direction width of the slider  740  in the inner gap  720   b . The axial-direction length of the first groove  720   c  structurally allows the second projection  740 A located on the most distal end side to be accommodated in the first groove  720   c  even after the second projection  740 A crosses over the first projection  720 A. 
     In the ligation device  701 , the first projection  720 A projects from the bottom portion of the first groove  720   c  toward the inner gap  720   b , and the top portion of each second projection  740 A is accommodated in the first groove  720   c . Thus, the slider  740  can be prevented from rotating in the circumferential direction with respect to the inner cylinder  720 . Thereby, the first projection  720 A and each second projection  740 A can be securely brought into contact with each other. 
     The ligation device  701  having such a configuration can also exhibit the same effect as of the ligation device  1  and the ligation device  601 . 
       FIG. 14A  is a partial sectional view of a ligation device  801  attached to the endoscope  2 , illustrating a state that a slider  840  is located on a proximal end side.  FIG. 14B ) is a partial sectional view taken along line XIVb-XIVb in  FIG. 14A .  FIG. 14A  illustrates only a part of the distal end portion of the endoscope  2  equipped with the ligation device  801 . In  FIG. 14B , the endoscope  2  is omitted. 
     Additionally, in  FIG. 14A , the left side of the figure is a distal end side (farther side) to be inserted into a body, and the right side is a proximal end side (hand side, nearer side). The endoscope  2  has the forceps hole  2   a  through which forceps not illustrated are inserted. 
     Note that, in this explanation of the ligation device  801 , the same members as in the ligation device  1  are given the same reference numerals as in the ligation device  1 , and detailed explanation of the same members is not repeated. 
     The ligation device  801  includes the joining member  10 , an inner cylinder  820 , the outer cylinder  30 , a slider  840 , the sealing member  50 , the ligation rings  60 ,  61  and  62 , and the tube  70 . 
     In the inner peripheral face  43  of the slider  840 , a part of the proximal end side more proximal than the annular groove  44   c  has a larger diameter. An inner gap  820   b  is formed between the enlarged-diameter part of the inner peripheral face  43  of the slider  840  and the outer peripheral face  20 A of the inner cylinder  820 . 
     On the outer peripheral face  20 A of the inner cylinder  820 , a first projection  820 A projecting into the inner gap  820   b  is placed. On the inner peripheral face  43  of the slider  840 , a second groove  840   b  extending along the axial direction is formed. On the bottom portion of the second groove  840   b , a plurality of second projections  840 A projecting into the inner gap  820   b  are placed along the axial direction. Configurations and positional relationships of the first projection  820 A and the plurality of second projections  840 A are almost the same as those of the first projection  620 A and the plurality of second projections  640 A in the ligation device  601 . A top portion of the first projection  820 A is accommodated in the second groove  840   b . That means, a height of the first projection  820 A is larger than a radial-direction width of the slider  840  in the inner gap  820   b.    
     In the ligation device  801  according to the sixth modification example, each second projection  840 A projects from the bottom portion of the second groove  840   b  toward the inner gap  820   b , and the top portion of the first projection  820 A is accommodated in the second groove  840   b . Thus, the slider  840  can be prevented from rotating in the circumferential direction with respect to the inner cylinder  820 . Thereby, the first projection  820 A and each second projection  840 A can be securely brought into contact with each other. 
     The ligation device  801  having such a configuration can also exhibit the same effect as of the ligation device  1  and the ligation device  601 . 
     In addition, as illustrated in  FIG. 15 , the inner cylinder  720  in the ligation device  701  and the slider  840  in the ligation device  801  may be combined. That means, the top portion of the first projection  720 A placed on the bottom portion of the first groove  720   c  may be accommodated in the second groove  840   b , and the top portion of each second projection  840 A placed on the bottom portion of the second groove  840   b  may be accommodated in the first groove  720   c.    
       FIG. 16A  is a partial sectional view of a ligation device  601 A attached to the endoscope  2 , illustrating a state that the slider  640  is located on the proximal end side. 
     In the ligation device  601  illustrated in  FIG. 11 , one first projection  620 A projecting into the inner gap  620   b  is placed on the outer peripheral face  20 A of the inner cylinder  620 , and the plurality of second projections  640 A projecting into the inner gap  620   b  are placed along the axial direction on the inner peripheral face  43  of the slider  640 . On the other hand, in the ligation device  601 A illustrated in  FIG. 16A , a plurality of the first projections  620 A projecting into the inner gap  620   b  are placed along the axial direction on the outer peripheral face  20 A of the inner cylinder  620 , and one piece of second projection  640 A projecting into the inner gap  620   b  is placed on the inner peripheral face  43  of the slider  640 , as illustrated in  FIG. 16A . 
     The plurality of first projections  620 A are located on the distal end side of the second projection  640 A in a state that the slider  640  is located on the proximal end side. The plurality of first projections  620 A and the second projection  640 A are arranged in a row along the axial direction. 
     The plurality of first projections  620 A are configured such that a distance between the first projections  620 A adjacent to each other is substantially equal to the distance between the ligation rings  60 ,  61  and  62  adjacent to each other. A distance between the second projection  640 A and the first projection  620 A located on the most proximal end side is set to a distance at which the ligation ring  60  is ejected from the slider  640  when the slider  640  advances and the second projection  640 A crosses over the first projection  620 A located on the most proximal end side. 
     A sum of heights of each first projection  620 A and the second projection  640 A in the radial direction of the slider  640  is structurally larger than a radial-direction width of the inner gap  620   b  (distance between the inner peripheral face  43  of the part with the enlarged diameter and the outer peripheral face  20 A). 
     A radial-direction height of one of the plurality of first projections  620 A is structurally different from radial-direction heights of the other remaining first projections  620 A. In the ligation device  601 A, the plurality of first projections  620 A are configured such that their radial-direction heights gradually increase toward the distal end side in the axial direction. Incidentally, the slider  640  in the ligation device  601 A is configured to have an axial-direction length larger than of the slider  640  in the ligation device  601 . The heights of the plurality of first projections may be equal to each other. 
     The ligation device  601 A can also exhibit the same effect as of the ligation device  1  and the ligation device  601 . 
       FIG. 16B  is a partial sectional view of a ligation device  701 A attached to the endoscope  2 , illustrating a state that the slider  740  is located on the proximal end side. 
     In the ligation device  701  illustrated in  FIG. 13 , one first projection  720 A projecting into the inner gap  720   b  is placed on the bottom portion of the first groove  720   c , and the plurality of second projections  740 A projecting into the inner gap  720   b  are placed along the axial direction on the inner peripheral face  43  of the slider  740 . On the other hand, in the ligation device  701 A, the plurality of first projections  720 A projecting into the inner gap  720   b  are placed along the axial direction on the bottom portion of the first groove  720   c , and one piece of second projection  740 A projecting into the inner gap  720   b  is placed on the inner peripheral face  43  of the slider  740 , as illustrated in  FIG. 16B . 
     Configurations and positional relationships of the plurality of first projections  720 A and the second projection  740 A are almost the same as those of the first projection  620 A and the plurality of second projections  640 A in  FIG. 16A . A top portion of each second projection  740 A is accommodated in the first groove  720   c . That means, a height of each second projection  740 A is larger than a radial-direction width of the slider  740  in the inner gap  720   b . Incidentally, the slider  740  in the ligation device  701 A is configured to have an axial-direction length larger than of the slider  740  in the ligation device  701 . 
     The ligation device  701 A can also exhibit the same effect as of the ligation device  1  and the ligation device  701 . 
       FIG. 16C  is a partial sectional view of a ligation device  801 A attached to the endoscope  2 , illustrating a state that the slider  840  is located on the proximal end side. 
     In the ligation device  801  in  FIG. 14 , one first projection  820 A projecting into the inner gap  820   b  is placed on the outer peripheral face  20 A of the inner cylinder  820 , and the plurality of second projections  840 A projecting into the inner gap  820   b  are placed along the axial direction on the bottom portion of the second groove  840   b . On the other hand, in the ligation device  801 A, the plurality of first projections  820 A projecting into the inner gap  820   b  are placed along the axial direction on the outer peripheral face  20 A of the inner cylinder  820 , and one piece of second projection  840 A projecting into the inner gap  820   b  is placed on the bottom portion of the second groove  840   b , as illustrated in  FIG. 16C . 
     Configurations and positional relationships of the plurality of first projections  820 A and the second projection  840 A are almost the same as those of the first projection  620 A and the plurality of second projections  640 A in the ligation device  601 A. Top portions of the plurality of first projections  820 A are accommodated in the second groove  840   b . That means, heights of the plurality of first projections  820 A are larger than a radial-direction width of the slider  840  in the inner gap  820   b . Incidentally, the slider  840  in the ligation device  801 A is configured to have an axial-direction length larger than of the slider  840  in the ligation device  801 . 
     The ligation device  801 A can also exhibit the same effect as of the ligation device  1  and the ligation device  801 . 
     Incidentally, in the aforementioned embodiments, each of the first projections  620 A,  720 A and  820 A may have an annular shape extending in the circumferential directions of the inner cylinders  620 ,  720  and  820  respectively. Each of the second projections  640 A,  740 A and  840 A may have an annular shape extending in the circumferential directions of the sliders  640 ,  740  and  840  respectively. Both of each of first projections  620 A,  720 A and  820 A and each of the second projections  640 A,  740 A and  840 A may have an annular shape extending in the circumferential directions of the inner cylinders  620 ,  720  and  820  and the sliders  640 ,  740  and  840  respectively. 
       FIG. 17A  is a partial sectional view of a ligation device  901  attached to the endoscope  2 , illustrating a state that a slider  940  is located on a proximal end side.  FIG. 17B  is a partial sectional view taken along line XVIIb-XVIIb in  FIG. 17A .  FIG. 17A  illustrates only a part of the distal end portion of the endoscope  2  equipped with the ligation device  901 . In  FIG. 17B , the endoscope  2  is omitted. 
     Additionally, in  FIG. 17A , the left side of the figure is a distal end side (farther side) to be inserted into a body, and the right side is a proximal end side (hand side, nearer side). The endoscope  2  has the forceps hole  2   a  through which forceps not illustrated are inserted. 
     Note that, in this explanation of the ligation device  901 , the same members as in the ligation device  1  are given the same reference numerals as in the ligation device  1 , and detailed explanation of the same members is not repeated. 
     The ligation device  901  includes the joining member  10 , the inner cylinder  20 , an outer cylinder  930 , a slider  940 , the sealing member  50 , the ligation rings  60 ,  61  and  62 , and the tube  70 . 
     On an outer peripheral face  41 A of the cylindrical portion  41  of the slider  940 , a plurality of (three) third projections  940 A projecting into the slide space  29  are placed along the axial direction. On an inner peripheral face  31 A of the outer cylindrical portion  31  of the outer cylinder  30 , a fourth projection  930 A projecting into the slide space  29  is placed. The slide space  29  corresponds to the outer gap. 
     The plurality of third projections  940 A are located on the proximal end side of the fourth projection  930 A in a state that the slider  940  is located on the proximal end side. Each third projection  940 A and the fourth projection  930 A have a saw-like sectional shape obtained by cutting the slider  940  along a plane including the axial direction of the slider  940 . Incidentally, the shape of the projections may be a trapezoid, a chevron shape, and a cylindrical shape, or the like. Each third projection  940 A and the fourth projection  930 A have a rectangular shape when viewed from the axial direction. The plurality of third projections  940 A and the fourth projection  930 A are arranged in a row along the axial direction. 
     The plurality of third projections  940 A are configured such that a distance between the third projections  940 A adjacent to each other is substantially equal to the distance between the ligation rings  60 ,  61  and  62  adjacent to each other. A distance between the fourth projection  930 A and the third projection  940 A located on the most distal end side is set to a distance at which the ligation ring  60  is ejected from the slider  940  when the slider  940  advances and the third projection  940 A located on the most distal end side crosses over the fourth projection  930 A. 
     A sum of heights of each third projection  940 A and the fourth projection  930 A in the radial direction of the slider  940  is structurally larger than a radial-direction width of the slide space  29  (distance between the outer peripheral face  41 A and the inner peripheral face  31 A. That means, as illustrated in  FIG. 17B , each third projection  940 A and the fourth projection  930 A share a part where they overlap each other when the ligation device  901  is viewed from the distal end side. 
     As illustrated in  FIG. 17A , a radial-direction height of one of the plurality of third projections  940 A is structurally different from radial-direction heights of the other remaining third projections  940 A. In the ligation device  901 , the plurality of third projections  940 A are configured such that their radial-direction heights gradually increase toward the proximal end side in the axial direction. The heights of the plurality of third projections may be equal to each other. 
       FIG. 18A  and  FIG. 18B  are diagrams explaining operations of the ligation device  901 . 
     A fluid is delivered to the slide space  29  through the tube  70  by operating a syringe not illustrated, and the slider  940  and the sealing member  50  are advanced using a pressure of the fluid as a driving source. As illustrated in  FIG. 18A , the third projection  940 A located on the most distal end side is made to abut on the fourth projection  930 A. When the driving force of the fluid for moving the slider  940  exceeds a predetermined magnitude, the third projection  940 A crosses over the fourth projection  930 A and move to the distal end side, as illustrated in  FIG. 18B . At this time, the ligation ring  60  is ejected from the slider  940 , moves to the distal end side on the tapered portion  27  while the diameter of the ligation ring  60  gradually decreases, and then the ligation ring  60  is ejected from the tapered portion  27 . Furthermore, when the third projection  940 A located in the middle in the axial direction crosses over the fourth projection  930 A by advancing the slider  940 , the ligation ring  61  is ejected from the slider  940 , and when the third projection  940 A located on the most proximal end side crosses over the fourth projection  930 A, the ligation ring  62  is ejected from the slider  940 . 
     The ligation device  901  is configured such that a sum of heights of each third projection  940 A and the fourth projection  930 A in the radial direction of the slider  940  is larger than a radial-direction width of the slide space  29 . Thus, for example, when the third projection  940 A crosses over the fourth projection  930 A by advancing the slider  940 , the ligation ring  60  is ejected from the slider  940 , and this configuration makes it possible to eject the ligation ring  60  at an intended timing. 
     Since the plurality of third projections  940 A are placed along the axial direction, the plurality of ligation rings  60 ,  61  and  62  can be sequentially ejected at an intended timing. A radial-direction height of one of the plurality of third projections  940 A is structurally different from radial-direction heights of the other remaining third projections  940 A. Thereby, a driving force for moving the slider  940  in ejecting the ligation rings  60 ,  61  and  62  can be changed. 
     The plurality of third projections  940 A are configured such that their radial-direction heights gradually increase toward the proximal end side in the axial direction. Thus, for example, it is possible to prevent an event that, after the third portion  940 A located on the most distal end side crosses over the fourth projection  930 A and the ligation ring  60  is ejected, the slider  940  advances, the third projection  940 A located in the middle crosses over the fourth projection  930 A, and the ligation ring  61  is erroneously ejected. 
     Furthermore, the ligation device  901  having such a configuration can also exhibit the same effect as of the ligation device  1 . 
       FIG. 19A  is a partial sectional view of a ligation device  1001  attached to the endoscope  2 , illustrating a state that a slider  1040  is located on a proximal end side.  FIG. 19B  is a partial sectional view taken along line XIXb-XIXb in  FIG. 19A .  FIG. 19A  illustrates only a part of the distal end portion of the endoscope  2  equipped with the ligation device  1001 . In  FIG. 19B , the endoscope  2  is omitted. 
     Additionally, in  FIG. 19A , the left side of the figure is a distal end side (farther side) to be inserted into a body, and the right side is a proximal end side (hand side, nearer side). The endoscope  2  has the forceps hole  2   a  through which forceps not illustrated are inserted. 
     Note that, in this explanation of the ligation device  1001 , the same members as in the ligation device  1  are given the same reference numerals as in the ligation device  1 , and detailed explanation of the same members is not repeated. 
     The ligation device  1001  includes the joining member  10 , the inner cylinder  20 , an outer cylinder  1030 , a slider  1040 , the sealing member  50 , the ligation rings  60 ,  61  and  62 , and the tube  70 . 
     On the outer peripheral face  41 A of the cylindrical portion  41  of the slider  1040 , a third groove  1040   b  extending the axial direction is formed. On a bottom portion of the third groove  1040   b , a plurality of third projections  1040 A projecting into the slide space  29  are placed along the axial direction. On the inner peripheral face  31 A of the outer cylindrical portion  31  of the outer cylinder  1030 , a fourth projection  1030 A projecting into the slide space  29  is placed. Configurations and positional relationships of the plurality of third projections  1040 A and the fourth projection  1030 A are almost the same as those of the plurality of third projections  940 A and the fourth projection  930 A in the ligation device  901 . A top portion of the fourth projection  1030 A is accommodated in the third groove  1040   b . That means, a height of the fourth projection  1030 A is larger than a radial-direction width of the slide space  29 . 
     In the ligation device  1001 , the plurality of third projections  1040 A project from the bottom portion of the third groove  1040   b  toward the slide space  29 , and the top portion of the fourth projection  1030 A is accommodated in the third groove  1040   b . Thus, the slider  1040  can be prevented from rotating in the circumferential direction with respect to the outer cylinder  1030 . Thereby, each third projection  1040 A and the fourth projection  1030 A can be securely brought into contact with each other. 
     The ligation device  1001  having such a configuration can also exhibit the same effect as of the ligation device  1  and the ligation device  901 . 
       FIG. 20A  is a partial sectional view of a ligation device  1101  attached to the endoscope  2 , illustrating a state that a slider  1140  is located on a proximal end side.  FIG. 20B  is a partial sectional view taken along line XXb-XXb in  FIG. 20A .  FIG. 20A  illustrates only a part of the distal end portion of the endoscope  2  equipped with the ligation device  1101 . In  FIG. 20B , the endoscope  2  is omitted. 
     Additionally, in  FIG. 20A , the left side of the figure is a distal end side (farther side) to be inserted into a body, and the right side is a proximal end side (hand side, nearer side). The endoscope  2  has the forceps hole  2   a  through which forceps not illustrated are inserted. 
     Incidentally, in this explanation of the ligation device  1101 , the same members as in the ligation device  1  are given the same reference numerals as in the ligation device  1 , and detailed explanation of the same members is not repeated. 
     The ligation device  1101  includes the joining member  10 , the inner cylinder  20 , an outer cylinder  1130 , the slider  1140 , the sealing member  50 , the ligation rings  60 ,  61  and  62 , and the tube  70 . 
     On the outer peripheral face  41 A of the cylindrical portion  41  of the slider  1140 , a plurality of third projections  1140 A projecting into the slide space  29  are placed. On the inner peripheral face  31 A of the outer cylindrical portion  31  of the outer cylinder  1130 , a fourth groove  1130   b  extending along the axial direction is formed. On the bottom portion of the fourth groove  1130   b , a fourth projections  1130 A projecting into the slide space  29  is placed. Configurations and positional relationships of the plurality of third projections  1140 A and the fourth projection  1130 A are almost the same as those of the plurality of third projections  1040 A and the fourth projection  1030 A in the ligation device  1001 . A top portion of each third projection  1140 A is accommodated in the fourth groove  1130   b . That means, a height of each third projection  1140 A is larger than a radial-direction width of the slider  1140  in the slide space  29 . 
     In the ligation device  1101 , the fourth projection  1130 A projects from the bottom portion of the fourth groove  1130   b  toward the slide space  29 , and the top portion of each third projection  1140 A is accommodated in the fourth groove  1130   b . Thus, the slider  1140  can be prevented from rotating in the circumferential direction with respect to the outer cylinder  1130 . Thereby, each third projection  1140 A and each fourth projection  1130 A can be securely brought into contact with each other. 
     The ligation device  1101  having such a configuration can also exhibit the same effect as of the ligation device  1  and the ligation device  901 . 
     In addition, as illustrated in  FIG. 21 , the slider  1040  and the outer cylinder  1130  may be combined. That means, the top portion of each third projection  1040 A placed on the bottom portion of the third groove  1040   b  may be accommodated in the fourth groove  1130   b , and the top portion of the fourth projection  1130 A placed on the bottom portion of the fourth groove  1130   b  may be accommodated in the third groove  1040   b.    
       FIG. 22A  is a partial sectional view of a ligation device  901 A attached to the endoscope  2 , illustrating a state that the slider  940  is located on the proximal end side. 
     In the ligation device  901 , the plurality of third projections  940 A projecting into the slide space  29  are placed along the axial direction on the outer peripheral face  41 A of the slider  940 , and the fourth projection  930 A projecting into the slide space  29  is placed on the inner peripheral face  31 A of the outer cylinder  930 . On the other hand, in the ligation device  901 A, one piece of third projection  940 A projecting into the slide space  29  is placed on the outer peripheral face  41 A of the slider  940 , and the plurality of fourth projections  930 A projecting into the slide space  29  are placed along the axial direction on the inner peripheral face  31 A of the outer cylinder  930 , as illustrated in  FIG. 22A . 
     The plurality of fourth projections  930 A are located on the distal end side of the third projection  940 A in a state that the slider  940  is located on the proximal end side. The third projection  940 A and the plurality of fourth projections  930 A are arranged in a row along the axial direction. 
     The plurality of fourth projections  930 A are configured such that a distance between the fourth projections  930 A adjacent to each other is substantially equal to the distance between the ligation rings  60 ,  61  and  62  adjacent to each other. A distance between the third projection  940 A and the fourth projection  930 A located on the most proximal end side is set to a distance at which the ligation ring  60  is ejected from the slider  940  when the slider  940  advances and the third projection  940 A crosses over the fourth projection  930 A located on the most proximal end side. 
     A sum of heights of the third projection  940 A and each fourth projection  930 A in the radial direction of the slider  940  is structurally larger than the radial-direction width of the slide space  29  (distance between the outer peripheral face  41 A and the inner peripheral face  31 A). 
     A radial-direction height of one of the plurality of fourth projections  930 A is structurally different from radial-direction heights of the other remaining fourth projections  930 A. In the ligation device  901 A, the plurality of fourth projections  930 A are configured such that their radial-direction heights gradually increase toward the distal end side in the axial direction. Incidentally, the slider  940  in the ligation device  901  is configured to have an axial-direction length larger than of the slider  940  according to the seventh modification example. The heights of the plurality of fourth projections may be equal to each other. 
     The ligation device  901 A can also exhibit the same effect as of the ligation device  1  and the ligation device  901 . 
       FIG. 22B  is a partial sectional view of a ligation device  1001 A attached to the endoscope  2 , illustrating a state that the slider  1040  is located on the proximal end side. 
     In the ligation device  1001 , the plurality of third projections  1040 A projecting into the slide space  29  are placed along the axial direction on the bottom portion of the third groove  1040   b , and one piece of fourth projection  1030 A projecting into the slide space  29  is placed on the inner peripheral face  31 A of the outer cylinder  1030 . On the other hand, in the ligation device  1001 A, one piece of third projection  1040 A projecting into the slide space  29  is placed on the bottom portion of the third groove  1040   b , and the plurality of fourth projections  1030 A projecting into the slide space  29  are placed along the axial direction on the inner peripheral face  31 A of the outer cylinder  1030 , as illustrated in  FIG. 22B . 
     Configurations and positional relationships of the third projections  1040 A and the plurality of fourth projections  1030 A are almost the same as those of the third projection  940 A and the plurality of fourth projections  930 A in  FIG. 22A . The top portion of each fourth projection  1030 A is accommodated in the third groove  1040   b . That means, the height of each fourth projection  1030 A is larger than the radial-direction width of the slider  1040  in the slide space  29 . Incidentally, the slider  1040  in the ligation device  1001 A is configured to have an axial-direction length larger than of the slider  1040  in the ligation device  1001 . 
     The ligation device  1001 A can also exhibit the same effect as of the ligation device  1  and the ligation device  1001 . 
       FIG. 22C  is a partial sectional view of a ligation device  1101 A attached to the endoscope  2 , illustrating a state that the slider  1140  is located on the proximal end side. 
     In the ligation device  1101 , the plurality of third projections  1140 A projecting into the slide space  29  are placed along the axial direction on the outer peripheral face  41 A of the slider  1140 , and one piece of fourth projection  1130 A projecting into the slide space  29  is placed on the bottom portion of fourth groove  1130   b . On the other hand, in the ligation device  1101 A, one piece of third projection  1140 A projecting into the slide space  29  is placed on the outer peripheral face  41 A of the slider  1140 , and the plurality of fourth projections  1130 A projecting into the slide space  29  are placed along the axial direction on the bottom portion of the fourth groove  1130   b , as illustrated in  FIG. 22C . 
     Configurations and positional relationships of the third projections  1140 A and the plurality of fourth projections  1130 A are almost the same as those of the third projection  940 A and the plurality of fourth projections  930 A in  FIG. 22A . The top portion of third projection  1140 A is accommodated in the fourth groove  1130   b . That means, the heights of the third projection  1140 A is larger than the radial-direction width of the slider  1140  in the slide space  29 . Incidentally, the slider  1140  in the ligation device  1101 A is configured to have an axial-direction length larger than of the slider  1140  in the ligation device  1101 . 
     The ligation device  1101 A can also exhibit the same effect as of the ligation device  1  and the ligation device  1101 . 
     Incidentally, in the aforementioned embodiments, each of the third projections  940 A,  1040 A and  1140 A may have an annular shape extending in the circumferential directions of the sliders  940 ,  1040  and  1140  respectively. Each of the fourth projections  930 A,  1030 A and  1130 A may have an annular shape extending in the circumferential directions of the outer cylinders  930 ,  1030  and  1130 , respectively. Both of each of the third projections  940 A,  1040 A and  1140 A and each of the fourth projections  930 A,  1030 A and  1130 A may have an annular shape extending in the circumferential directions of the sliders  940 ,  1040 ,  1140  and the outer cylinders  930 ,  1030  and  1130  respectively. 
       FIG. 23A  is a sectional view of a ligation device  1201  attached to the endoscope  2 , illustrating a state that a slider  1240  is located on a proximal end side.  FIG. 23B  is a sectional view taken along line XXIIIb-XXIIIb in  FIG. 23A .  FIG. 23A  illustrates only a part of the distal end portion of the endoscope  2  equipped with the ligation device  1201 . In  FIG. 23B , the endoscope  2  is omitted. 
     Additionally, in  FIG. 23A , the left side of the figure is a distal end side (farther side) to be inserted into a body, and the right side is a proximal end side (hand side, nearer side). The endoscope  2  has the forceps hole  2   a  through which forceps not illustrated are inserted. 
     Incidentally, in this explanation of the ligation device  1201 , the same members as in the ligation device  1  are given the same reference numerals as in the ligation device  1 , and detailed explanation of the same members is not repeated. 
     The ligation device  1201  includes the joining member  10 , the inner cylinder  20 , an outer cylinder  1230 , a slider  1240 , the sealing member  50 , the ligation rings  60 ,  61  and  62 , and the tube  70 . 
     In the inner peripheral face  43  of the slider  1240 , a part of the proximal end side of the annular groove  44   c  has a larger diameter. The inner gap  20   b  is formed between the enlarged-diameter part of the inner peripheral face  43  of the slider  1240  and the outer peripheral face  20 A of the inner cylinder  20 . 
     On the inner peripheral face  43  of the slider  1240 , a plurality of sixth projections  1240 A that project into the inner gap  20   b  to abut on the outer peripheral face  20 A of the inner cylinder  20  are placed. Each sixth projection  1240 A extends along the axial direction. On the inner peripheral face  31 A of the outer cylindrical portion  31  of the outer cylinder  30 , a plurality of eighth projections  1230 A that project into the slide space  29  to abut on the outer peripheral face  41 A of the slider  1240  are placed. Each eighth projection  1230 A extends along the axial direction. 
     According to the configuration of the ligation device  1201 , when the slider  1240  moves in the axial direction, straightness of the slider  1240  can be improved without increasing the frictional resistance between the inner cylinder  20  and the outer cylinder  30 . 
     The ligation device  1201  can also exhibit the same effect as of the ligation device  1 . 
     Incidentally, as represented by the dashed line in  FIG. 23B , grooves  20   c  and  1240   b  extending along the axial direction may be formed on the outer peripheral face  20 A of the inner cylinder  20  and the outer peripheral face  41 A of the slider  1240  respectively, so that top portions of the sixth projections  1240 A and the eighth projections  1230 A are accommodated in the grooves. Although the sixth projections  1240 A and the eighth projections  1230 A are placed on the ligation device  1201 , either the sixth or eighth projections may be placed. 
       FIG. 24A , is a sectional view of a ligation device  1301  attached to the endoscope  2 , illustrating a state that a slider  1340  is located on a proximal end side.  FIG. 24B  is a sectional view taken along line XXIVb-XXIVb in  FIG. 24A .  FIG. 24A  illustrates only a part of the distal end portion of the endoscope  2  equipped with the ligation device  1301 . In  FIG. 24B , the endoscope  2  is omitted. 
     Additionally, in  FIG. 24A , the left side of the figure is a distal end side (farther side) to be inserted into a body, and the right side is a proximal end side (hand side, nearer side). The endoscope  2  has the forceps hole  2   a  through which forceps not illustrated are inserted. 
     Incidentally, in this explanation of the ligation device  1301 , the same members as in the ligation device  1  are given the same reference numerals as in the ligation device  1 , and detailed explanation of the same members is not repeated. 
     The ligation device  1301  includes the joining member  10 , an inner cylinder  1320 , the outer cylinder  30 , a slider  1340 , the sealing member  50 , the ligation rings  60 ,  61  and  62 , and the tube  70 . 
     In the inner peripheral face  43  of the slider  1340 , a part of the proximal end side of the annular groove  44   c  has a larger diameter. The inner gap  20   b  is formed between the enlarged-diameter part of the inner peripheral face  43  of the slider  1340  and the outer peripheral face  20 A of the inner cylinder  1320 . 
     On the outer peripheral face  20 A of the inner cylinder  1320 , a plurality of fifth projections  1320 A that project into the inner gap  20   b  to abut on the inner peripheral face  43  of the slider  1340  are placed. Each fifth projection  1320 A extends along the axial direction. On the outer peripheral face  41 A of the slider  1340 , a plurality of seventh projections  1340 A that project into the slide space  29  to abut on the inner peripheral face  31 A of the outer cylinder  30  are placed. Each seventh projection  1340 A extends along the axial direction. 
     According to the configuration of the ligation device  1301 , when the slider  1340  moves in the axial direction, straightness of the slider  1340  can be improved without increasing the frictional resistance between the inner cylinder  1320  and the outer cylinder  30 . 
     The ligation device  1301  can also exhibit the same effect as of the ligation device  1 . 
     As represented by the dashed line in  FIG. 24B , grooves  1340   b  and  31   b  extending along the axial direction may be formed on the inner peripheral face  43  of the slider  1340  and the inner peripheral face  31 A of the outer cylinder  30  respectively, so that top portions of the fifth projections  1320 A and the seventh projections  1340 A are accommodated in the grooves. Although the fifth projections  1320 A and the seventh projections  1340 A are placed on the ligation device  1301 , either the fifth or seventh projections may be placed. In the ligation device  1301 , the sixth projections  1240 A and eighth projections  1230 A in the ligation device  1201  may be placed in addition to the fifth projections  1320 A and the seventh projections  1340 A.