Patent Publication Number: US-2019180227-A1

Title: Stock management device, customer terminal, and stock management method

Description:
TECHNICAL FIELD 
     The present disclosure relates to a stock management device, a customer terminal, an item sales system, a stock management method, a display control method, and a recording medium. 
     BACKGROUND ART 
     There are an increasing of doing online shopping to purchase an item through the Internet. Further, an item sales method called a mobile supermarket using a mobile sales vehicle has been proposed (NPL 1). 
     As a technology of combining the above, a technology of ordering, through a network, an item being sold by a mobile sales vehicle and purchasing the ordered item at a mobile sales vehicle is disclosed (PTL 1 and PTL 2). 
     Further, as a technology related to online shopping, for example, a method of supporting in-store picking of an item to be ordered is described in PTL 3. 
     CITATION LIST 
     Patent Literature 
     
         
         PTL 1: Japanese Unexamined Patent Application Publication No. 2011-221984 
         PTL 2: Japanese Unexamined Patent Application Publication No. 2008-123278 
         PTL 3: Japanese Unexamined Patent Application Publication No. 2009-151623 
       
    
     Non Patent Literature 
     
         
         NPL 1: “Mobile Supermarket Tokushimaru,” [online], [retrieved on Jul. 13, 2016], retrieved from the Internet: &lt;http://www.tokushimaru.jp/&gt; 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     Item purchase by online shopping takes at least several hours from ordering of an item to delivery to the purchaser, and therefore it takes a long time for actual delivery after ordering. However, in the case of item purchase by online shopping, for example, there is a benefit that a customer staying indoors can receive an item without going outdoors. Further, in item sale by a mobile sales vehicle, an item is displayed on a luggage carrier of the mobile sales vehicle as is the case with a common supermarket, and therefore a customer can actually take an item in hand and purchase the item at the mobile sales vehicle. Accordingly, for example, when a supermarket does not exist close to a customer and a mobile sales vehicle sells items close to the customer, there is a benefit that the customer can get an item to be purchased at a storefront of the mobile sales vehicle, without visiting a distant supermarket. A technology allowing a customer to acquire both such a benefit of using online shopping and such a benefit by using a mobile sales vehicle is being sought. In order to acquire the both benefits, the present inventors have found a method for unitarily managing stock of items being sold at a mobile sales vehicle and stock of items being sold on online shop. However, due to unitarily management of stock, when an item of which a customer using online shopping desires to purchase is being sold at a mobile sales vehicle, the item may possibly be purchased by a customer using the mobile sales vehicle. Consequently, a customer using online shopping may not be able to purchase the desired item after determining to purchase the item. 
     An object of the present disclosure is to provide a technology enabling a customer purchasing an item by online shopping to understand sales status of items at a mobile sales vehicle and also to have both a benefit of online shopping and a benefit of using a mobile sales vehicle. 
     Solution to Problem 
     A stock management device according to one aspect of the present disclosure includes: 
     management means for managing stock information about stock of an item held by each of a plurality of mobile sales vehicles; 
     first reception means for receiving, from each of the plurality of mobile sales vehicles, sales information indicating an item sold at a storefront of the mobile sales vehicle and state information indicating a state of the mobile sales vehicle; 
     first transmission means for transmitting, to a customer terminal, sales state information indicating whether or not the mobile sales vehicle is selling an item at a storefront of the mobile sales vehicle and the stock information, the sales state information being generated based on the state information; 
     second reception means for receiving, from a customer terminal transmitting the stock information and the sales state information, order information including information about an item ordered based on the stock information and the sales state information; and 
     second transmission means for transmitting the order information to the mobile sales vehicle holding the ordered item included in the order information, wherein 
     the management means updates the stock information based on at least one of the sales information and the order information. 
     A customer terminal according to one aspect of the present disclosure includes: 
     reception means for receiving, from a stock management device managing stock information about stock of an item held by each of a plurality of mobile sales vehicles, sales state information indicating whether or not the mobile sales vehicle is selling an item at a storefront of the mobile sales vehicle, the sales state information being generated based on state information indicating a state of each of the plurality of mobile sales vehicles, and the stock information; and 
     display control means for controlling a display device to display an ordering screen for receiving an order from a customer, the ordering screen being generated based on the stock information and the sales state information. 
     An item sales system according to one aspect of the present disclosure includes: 
     a stock management device; 
     an on-board device being loaded on each of a plurality of mobile sales vehicles and transmitting, to the stock management device, sales information indicating an item sold at a storefront of each of the plurality of mobile sales vehicle and state information indicating a state of the mobile sales vehicle; and 
     one or more customer terminals, wherein 
     the stock management device includes:
         management means for managing stock information about stock of an item held by each of the plurality of mobile sales vehicles;   first reception means for receiving the sales information and the state information;   first transmission means for transmitting, to the customer terminal, sales state information indicating whether or not the mobile sales vehicle is selling an item at the storefront, the sales state information being generated based on the state information, and the stock information;   second reception means for receiving, from a customer terminal transmitting the stock information and the sales state information, order information including information about an item ordered based on the stock information and the sales state information; and   second transmission means for transmitting the order information to the on-board device on the mobile sales vehicle holding the ordered item included in the order information, wherein       

     the management means updates the stock information based on at least one of the sales information and the order information. 
     A stock management method according to one aspect of the present disclosure includes: 
     managing stock information about stock of an item held by each of a plurality of mobile sales vehicles; 
     receiving, from each of the plurality of mobile sales vehicles, sales information indicating an item sold at a storefront of the mobile sales vehicle; 
     receiving, from each of the plurality of mobile sales vehicles, state information indicating a state of the mobile sales vehicle; 
     transmitting, to a customer terminal, sales state information indicating whether or not the mobile sales vehicle is selling an item at the storefront, the sales state information being generated based on the state information, and the stock information; 
     receiving, from a customer terminal transmitting the stock information and the sales state information, order information including information about an item ordered based on the stock information and the sales state information; and 
     transmitting the order information to the mobile sales vehicle holding the ordered item included in the order information, wherein 
     updating the stock information based on at least one of the sales information and the order information. 
     A display control method according to one aspect of the present disclosure includes: 
     receiving, from a stock management device managing stock information about stock of an item held by each of a plurality of mobile sales vehicles, sales state information indicating whether or not the mobile sales vehicle is selling an item at a storefront of the mobile sales vehicle, the sales state information being generated based on state information indicating a state of each of the plurality of mobile sales vehicles, and the stock information; and 
     controlling a display device to display an ordering screen for receiving an order from a customer, the ordering screen being generated based on the stock information and the sales state information. 
     A stock management method in an item sales system according to one aspect of the present disclosure, the item sales system including a stock management device, an on-board device being loaded on each of a plurality of mobile sales vehicles, and one or more customer terminals, the stock management method includes: 
     managing, by the stock management device, stock information about stock of an item held by each of the plurality of mobile sales vehicles; 
     transmitting, by the on-board device, to the stock management device, sales information indicating an item sold at a storefront of the mobile sales vehicle loaded with the on-board device and state information indicating a state of the mobile sales vehicle; 
     receiving, by the stock management device, the sales information; 
     receiving, by the stock management device, the state information; 
     transmitting, by the stock management device, to the customer terminal, sales state information indicating whether or not the mobile sales vehicle is selling an item at the storefront, the sales state information being generated based on the state information, and the stock information; 
     receiving, by the customer terminal, the stock information and the sales state information; 
     transmitting, by the customer terminal, to the stock management device, order information including information about an item ordered based on the stock information and the sales state information; 
     receiving, by the stock management device, the order information from the customer terminal; 
     transmitting, by the stock management device, the order information to the on-board device on the mobile sales vehicle holding the ordered item included in the order information; and 
     updating, by the stock management device, the stock information based on at least one of the sales information and the order information. 
     A computer program implementing, with a computer, the stock management device, the customer terminal, the item sales system, or the respective methods that are described above, and a computer-readable, non-transitory recording medium storing the computer program are also included in the scope of the present disclosure. 
     Advantageous Effects of Invention 
     The present disclosure enables a customer purchasing an item by online shopping to understand sales status of an item at a mobile sales vehicle and also to have both a benefit of online shopping and a benefit of using a mobile sales vehicle. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a functional block diagram illustrating a functional configuration example of a stock management device according to a first example embodiment. 
         FIG. 2  is a flowchart illustrating an example of a processing flow in the stock management device according to the first example embodiment. 
         FIG. 3  is a functional block diagram illustrating a functional configuration example of a customer terminal communicating with the stock management device according to the first example embodiment. 
         FIG. 4  is a flowchart illustrating an example of a processing flow in the customer terminal communicating with the stock management device according to the first example embodiment. 
         FIG. 5  is a functional block diagram illustrating a functional configuration example of an item sales system including the stock management device according to the first example embodiment. 
         FIG. 6  is a flowchart illustrating an example of a processing flow in the item sales system including the stock management device according to the first example embodiment. 
         FIG. 7  is a block diagram illustrating a configuration example of an item sales system according to a second example embodiment. 
         FIG. 8  is a diagram for illustrating a use scene of the item sales system according to the second example embodiment. 
         FIG. 9  is a functional block diagram illustrating a functional configuration example of a stock management device in the item sales system according to the second example embodiment. 
         FIG. 10  is a diagram illustrating an example of stock information stored by a stock information storage unit according to the second example embodiment. 
         FIG. 11  is a diagram illustrating an example of customer information stored by a customer information storage unit according to the second example embodiment. 
         FIG. 12  is a functional block diagram illustrating a functional configuration example of an on-board device in the item sales system according to the second example embodiment. 
         FIG. 13  is a functional block diagram illustrating a functional configuration example of a customer terminal in the item sales system according to the second example embodiment. 
         FIG. 14  is a flowchart illustrating an example of a processing flow of updating stock information, based on sales information, in the item sales system according to the second example embodiment. 
         FIG. 15  is a flowchart illustrating an example of a flow of transmission processing of state information by the on-board device in the item sales system according to the second example embodiment. 
         FIG. 16  is a flowchart illustrating an example of a flow of sales processing of an item by online shopping in the item sales system according to the second example embodiment. 
         FIG. 17  is a flowchart illustrating an example of a flow of the sales processing of an item by online shopping in the item sales system according to the second example embodiment. 
         FIG. 18  is a diagram illustrating an example of an ordering screen displayed by a display unit. 
         FIG. 19  is a diagram illustrating another example of an ordering screen displayed by the display unit. 
         FIG. 20  is a diagram illustrating an example of a confirmation screen displayed by the display unit. 
         FIG. 21  is a diagram illustrating an example of an ordered items confirmation screen displayed by the display unit. 
         FIG. 22  is a diagram illustrating another example of an ordered items confirmation screen displayed by the display unit. 
         FIG. 23  is a functional block diagram illustrating a functional configuration example of an on-board device in an item sales system according to a third example embodiment. 
         FIG. 24  is a diagram illustrating an example of an ordering screen displayed by a display unit. 
         FIG. 25  is a diagram illustrating an example of a confirmation screen displayed by the display unit. 
         FIG. 26  is a flowchart illustrating an example of a processing flow in the item sales system according to the third example embodiment. 
         FIG. 27  is a functional block diagram illustrating a functional configuration example of a stock management device in an item sales system according to a modified example of the third example embodiment. 
         FIG. 28  is a diagram exemplarily illustrating a hardware configuration of a computer (information processing device) capable of implementing the respective example embodiments. 
     
    
    
     EXAMPLE EMBODIMENT 
     First Example Embodiment 
     A first example embodiment of the present disclosure will be described with reference to drawings. A stock management device  10  managing stock information about stock of an item held by each of a plurality of mobile sales vehicles will be described in the present example embodiment. A mobile sales vehicle is a vehicle capable of moving to a predetermined location in accordance with a predetermined traveling route or in a predetermined area, and selling items loaded on a luggage carrier of the vehicle, at the destination. A mobile sales vehicle can also receive an order for items loaded on the vehicle, while opening a luggage carrier and selling items loaded on the luggage carrier, or through a network while moving. Then, based on the received order, the mobile sales vehicle delivers the item to a customer who ordered. As described above, a mobile sales vehicle sells items loaded on itself not only at its storefront but also through a network, and therefore selling items displayed at the storefront may compete with selling through a network. A technology of providing both a benefit of online shopping and a benefit of using a mobile sales vehicle even when items are in such a competition will be described in the present disclosure.  FIG. 1  is a functional block diagram illustrating a functional configuration example of a stock management device  10  according to the present example embodiment. As illustrated in  FIG. 1 , the stock management device  10  according to the present example embodiment includes a management unit  11 , a first reception unit  12 , a first transmission unit  13 , a second reception unit  14 , and a second transmission unit  15 . 
     The management unit  11  manages stock information about stock of an item held by each of a plurality of mobile sales vehicles. The stock information includes at least information (for example, an item name and an item identifier) for identifying an item held by each of the plurality of mobile sales vehicles and a quantity of the item. The management unit  11  manages stock information for each mobile sales vehicle. Stock information managed by the management unit  11  may be stored in a storage unit provided inside the stock management device  10  or may be stored in a storage device separate from the stock management device  10 . 
     Further, the management unit  11  updates stock information, based on sales information received by the first reception unit  12  and/or order information received by the second reception unit  14 . 
     The first reception unit  12  receives, from each of a plurality of mobile sales vehicles, sales information indicating an item sold at a storefront of the mobile sales vehicle and state information indicating a state of the mobile sales vehicle. The sales information includes at least information (for example, an item name and an item identifier) for identifying an item sold at the storefront of the mobile sales vehicle and a quantity of the item. The state information, for example, is generated based on at least one of a signal indicating a change in movement of or an operating state of a mobile sales vehicle, a signal indicating a change in an engine of the mobile sales vehicle or an operating state of the engine, and a signal indicating whether or not the mobile sales vehicle is open for business. A mobile sales vehicle is open for business represents a state of the mobile sales vehicle is selling items loaded on itself at its storefront. In other words, a mobile sales vehicle being open for business represents a state in which a customer using the mobile sales vehicle can purchase an item at the storefront of the mobile sales vehicle. The state information is generated, for example, by a state change being detected when a mobile sales vehicle starts moving from a stopped state, based on a signal indicating the detected state change. The first reception unit  12  provides the received sales information and state information to the management unit  11 . 
     The first transmission unit  13  transmits, to a customer terminal, sales state information indicating whether or not a mobile sales vehicle is selling items at its storefront, the sales state information being generated based on state information, and stock information. 
     The second reception unit  14  receives order information including information about an ordered item from a customer terminal to which stock information and sales state information are transmitted by the first transmission unit  13 . The ordered item is placed an order based on the stock information and the sales state information. The order information includes at least information for identifying a customer ordering an item, information (for example, an item name and an item identifier) for identifying the ordered item, the item being included in the stock information managed by the management unit  11 , and a quantity of the item. The second reception unit  14  provides the received order information to the management unit  11 . 
     The second transmission unit  15  transmits order information to a mobile sales vehicle holding an ordered item. Specifically, the second transmission unit  15  receives, from the management unit  11 , information indicating a mobile sales vehicle holding an ordered item along with order information and transmits the order information to the mobile sales vehicle. 
     Next, a processing flow in the stock management device  10  according to the present example embodiment will be described with reference to  FIG. 2 .  FIG. 2  is a flowchart illustrating an example of a processing flow in the stock management device  10  according to the present example embodiment. It is assumed in  FIG. 2  that the management unit  11  in the stock management device  10  manages stock information about stock of an item held by a plurality of mobile sales vehicles, for each mobile sales vehicle. 
     As illustrated in  FIG. 2 , first, the first reception unit  12  in the stock management device  10  receives, from each of a plurality of mobile sales vehicles, sales information indicating an item sold at the storefront of the mobile sales vehicle (Step S 21 ). Further, the first reception unit  12  receives, from each of a plurality of mobile sales vehicles, state information indicating a state of the mobile sales vehicle (Step S 22 ). 
     After Step S 22  ends, the first transmission unit  13  transmits, to a customer terminal, sales state information indicating whether or not a mobile sales vehicle is selling items at its storefront, the sales state information being generated based on state information, and the stock information (Step S 23 ). The sales state information transmitted to the customer terminal by the first transmission unit  13  is generated for each mobile sales vehicle, based on state information about the mobile sales vehicle. Then, the first transmission unit  13  transmits, to the customer terminal, the sales state information generated for each mobile sales vehicle. 
     Then, the second reception unit  14  receives, from the customer terminal to which the stock information and the sales state information are transmitted by the first transmission unit  13  in Step S 23 , order information including information about an item ordered based on the stock information and the sales state information (Step S 24 ). 
     Then, the second transmission unit  15  transmits the order information to a mobile sales vehicle holding the ordered item included in the order information received in Step S 24  (Step S 25 ). Step S 21  may be performed after any of Steps S 22  to S 25  or may be performed at a time with any of Steps S 22  to S 25 . 
     Further, when Step S 21  and/or S 25  ends, the management unit  11  updates the stock information, based on the sales information and/or the order information (Step S 26 ). Specifically, when Step S 21  ends, the management unit  11  updates stock information about stock held by a mobile sales vehicle transmitting sales information, based on the sales information. Further, when Step S 25  ends, the management unit  11  updates stock information about stock held by a mobile sales vehicle to which the second transmission unit  15  transmitted the order information, based on the order information. 
     The above concludes the processing by the stock management device  10 . 
     As described above, the management unit  11  updates stock information based on at least one of sales information received by the first reception unit  12  and order information received by the second reception unit  14 . The stock management device  10  manages both stock for mobile sale by a mobile sales vehicle and stock for an online shop. Thus, the stock management device  10 , for example, reflects stock for mobile sale in which items sold by mobile sale to stock for an online shop. Further, for example, when an order for an item is placed by an online shop, stock information about stock of items available for sale at a mobile sales vehicle is also updated. Consequently, both a customer using a mobile sales vehicle and a customer doing online shopping can confirm items in stock purchasable at the time. Accordingly, items held by a mobile sales vehicle can be sold both at the mobile sales vehicle and on an online shop. 
     Further, the second transmission unit  15  transmits order information to a mobile sales vehicle holding an ordered item included in the order information. Consequently, a driver of a mobile sales vehicle receiving the order information can deliver an item to a customer who ordered the item held by the mobile sales vehicle. 
     Further, the first transmission unit  13  transmits, to a customer terminal, sales state information indicating whether or not a mobile sales vehicle is selling items at the storefront, the sales state information being generated based on state information, and stock information. Consequently, a customer doing online shopping by use of a customer terminal can confirm stock information, and whether or not the mobile sales vehicle is selling the items included in the stock information is selling items at its storefront. Accordingly, the customer can do online shopping while understanding whether or not an item of which the customer desires to purchase is being also sold at the time at the storefront of the mobile sales vehicle. 
     Accordingly, the stock management device  10  according to the present example embodiment enables a customer purchasing an item by online shopping to understand sales status of the item at a mobile sales vehicle and also to have both a benefit of online shopping and a benefit of using a mobile sales vehicle. 
     Next, a customer terminal communicating with the stock management device  10  will be described.  FIG. 3  is a functional block diagram illustrating a functional configuration example of a customer terminal  30  communicating with the stock management device  10  according to the present example embodiment. 
     As illustrated in  FIG. 3 , the customer terminal  30  includes a reception unit  31  and a display control unit  32 . The reception unit  31  receives, from the aforementioned stock management device  10 , sales state information indicating whether or not a mobile sales vehicle is selling items at its storefront. The sales state information is generated based on state information indicating a state of each of a plurality of mobile sales vehicles. Further, the reception unit  31  receives stock information from the stock management device  10 . The reception unit  31  provides the received sales state information and stock information to the display control unit  32 . 
     The display control unit  32  controls a display device to display an ordering screen for receiving an order from a customer, the ordering screen being generated based on stock information and sales state information. At this time, when the sales state information indicates that a mobile sales vehicle sells items at its storefront of, it is preferable that the display control unit  32  gets an item included in stock information related to the mobile sales vehicle displayed on the ordering screen in a different manner from an item included in stock information related to another mobile sales vehicle. 
     Next, a processing flow in the customer terminal  30  will be described with reference to  FIG. 4 .  FIG. 4  is a flowchart illustrating an example of a processing flow in a customer terminal  30  communicating with the stock management device  10  according to the present example embodiment. 
     First, the reception unit  31  receives, from the stock management device, sales state information indicating whether or not a mobile sales vehicle is selling items at its storefront, the sales state information being generated based on state information indicating a state of each of a plurality of mobile sales vehicles, and stock information (Step S 41 ). Then, the display control unit  32  causes a display device to display an ordering screen for receiving an order from a customer, the ordering screen being generated based on the stock information and the sales state information (Step S 42 ). 
     The above concludes the processing by the customer terminal  30 . 
     As described above, the customer terminal  30  displays an ordering screen based on stock information and sales state information. Accordingly, a customer doing online shopping by use of the customer terminal  30  can confirm stock information, and whether or not the mobile sales vehicle selling the items included in the stock information is selling items at its storefront. Consequently, the customer can do online shopping while, for example, understanding whether or not an item of which the customer desires to purchase is being also sold at the time at the storefront of the mobile sales vehicle. Consequently, for example, when a customer doing online shopping prefers to securely get items that the customer desires to purchase, the customer can take a measure of ordering items not being sold at a storefront of a mobile sales vehicle at the time. 
     Further, an item sales system  1  including the stock management device  10  according to the present example embodiment will be described with reference to  FIG. 5 .  FIG. 5  is a functional block diagram illustrating a functional configuration example of the item sales system  1  including the stock management device  10  according to the present example embodiment. As illustrated in  FIG. 5 , the item sales system  1  includes the stock management device  10 , a plurality of on-board devices  20 , and one or a plurality of customer terminals  30 . The stock management device  10  included in  FIG. 5  has a configuration similar to that of the stock management device  10  described by use of  FIG. 1 . Further, the customer terminal  30  included in  FIG. 5  includes a function similar to that of the customer terminal  30  described by use of  FIG. 3 . 
     An on-board device  20  is loaded on each of a plurality of mobile sales vehicles and transmits, to the stock management device  10 , sales information indicating an item sold at the storefront of each of the plurality of mobile sales vehicles. Further, an on-board device  20  transmits, to the stock management device  10 , state information indicating a state of a mobile sales vehicle loaded with the on-board device  20 . Then, a first reception unit  12  in the stock management device  10  receives the sales information and the state information. 
     A first transmission unit  13  in the stock management device  10  transmits, to a customer terminal  30 , stock information and sales state information generated based on state information. 
     Further, a second reception unit  14  in the stock management device  10  receives order information transmitted from each customer terminal  30 . 
     A management unit  11  in the stock management device  10  updates stock information based on at least one of sales information received by the first reception unit  12  and order information received by the second reception unit  14 . 
     Further, a second transmission unit  15  transmits order information to an on-board device  20  on a mobile sales vehicle holding an ordered item included in the order information. 
     Next, a processing flow in the item sales system  1  including the stock management device  10  according to the present example embodiment will be described with reference to  FIG. 6 .  FIG. 6  is a flowchart illustrating an example of a processing flow in the item sales system  1  including the stock management device  10  according to the present example embodiment. It is assumed in  FIG. 6  that the management unit  11  in the stock management device  10  manages stock information about stock of an item held by a plurality of mobile sales vehicles, for each mobile sales vehicle. Further, in  FIG. 6 , processing by an on-board device  20  is described on the left, processing by the stock management device  10  at the center, and processing by a customer terminal  30  on the right; and a broken arrow between the respective processing steps represents a flow of primary information. An information flow is not limited to a direction of an arrow, and for example, an ACKnowledgement (ACK) may be transmitted in a direction reverse to the arrow. 
     As illustrated in  FIG. 6 , an on-board device  20  transmits, to the stock management device  10 , sales information indicating an item sold at a storefront of a mobile sales vehicle loaded with the on-board device  20  (Step S 61 ). Further, the on-board device  20  transmits, to the stock management device  10 , state information indicating a state of the mobile sales vehicle (Step S 62 ). Steps S 61  and S 62  may be performed at a time or may be performed in reverse order. 
     The first reception unit  12  in the stock management device  10  receives the sales information (Step S 63 ). Further, the first reception unit  12  receives the state information (Step S 64 ). Then, the first transmission unit  13  transmits, to a customer terminal  30 , stock information and sales state information generated based on the state information (Step S 65 ). The first transmission unit  13  may transmit the stock information and the sales state information separately. The sales state information may be transmitted every time the state information is received, as long as the transmission is performed after the stock information is transmitted. 
     Then, the customer terminal  30  receives, from the stock management device  10 , the stock information and the sales state information (Step S 66 ), and transmits, to the stock management device  10 , order information including information about an item ordered based on the received stock information and sales state information (Step S 67 ). Steps S 61 , S 62 , and S 67  are performed asynchronously, and an order thereof is not particularly limited. 
     The second reception unit  14  in the stock management device  10  receives the order information from the customer terminal  30  (Step S 68 ). 
     When Step S 68  ends, the second transmission unit  15  transmits the order information to an on-board device  20  loaded on a mobile sales vehicle holding the ordered item included in the order information received by the second reception unit  14  in Step S 68  (Step S 69 ). Further, when Step S 63  and/or S 69  ends, the management unit  11  updates the stock information, based on the sales information and/or the order information (Step S 70 ). Specifically, when updating the stock information based on the sales information, the management unit  11  updates, based on the sales information, stock information about stock held by the mobile sales vehicle transmitting the sales information. Further, when updating the stock information based on the order information, the management unit  11  updates, based on the order information, stock information about stock held by the mobile sales vehicle to which the order information is transmitted by the second transmission unit  15  in Step S 69 . 
     When Step S 69  ends, the on-board device  20  receives the order information (Step S 71 ). 
     In the item sales system  1 , when an item is purchased at a mobile sales vehicle loaded with an on-board device  20 , Step S 61  is executed again. Further, when a customer starts shopping by use of a customer terminal  30 , Step S 66  is executed again. 
     Thus, the stock management device  10  executes the processing illustrated in the flowchart in  FIG. 6  every time a customer purchases an item. 
     As described above, in the item sales system  1 , the management unit  11  in the stock management device  10  updates stock information, based on sales information received by the first reception unit  12  and order information received by the second reception unit  14 . Further, the second transmission unit  15  transmits order information to an on-board device  20  on a mobile sales vehicle holding an ordered item included in the order information. Consequently, the mobile sales vehicle loaded with the on-board device  20  can deliver the ordered item to a customer ordering the item. 
     Further, the stock management device  10  transmits stock information and sales state information to a customer terminal  30 . Consequently, a customer using the customer terminal  30  can place an order, based on the stock information and the sales state information. Consequently, the customer can do online shopping while, for example, understanding whether or not an item of which the customer desires to purchase is being also sold at the time at the storefront of the mobile sales vehicle. 
     Accordingly, the item sales system  1  including the stock management device  10  according to the present example embodiment enables a customer purchasing an item by online shopping to understand sales status of the item at a mobile sales vehicle and also to have both a benefit of online shopping and a benefit of using a mobile sales vehicle. 
     Second Example Embodiment 
     Next, a second example embodiment of the present disclosure based on the aforementioned first example embodiment will be described with reference to drawings. First,  FIG. 7  illustrates a configuration example of an item sales system  2  according to the present example embodiment. As illustrated in  FIG. 7 , the item sales system  2  according to the present example embodiment includes a stock management device  100 , a plurality of on-board devices  200 , and one or a plurality of customer terminals  300 . The stock management device  100  communicates with on-board devices  200  and customer terminals  300  through a network. A customer terminal  300  may be a mobile terminal or may be a desktop terminal. 
       FIG. 8  is a diagram for illustrating a use scene of the item sales system  2  according to the present example embodiment. An on-board device  200  included in the item sales system  2  is a device loaded on each of a plurality of mobile sales vehicles. While  FIG. 8  illustrates two mobile sales vehicles (SA, SB), a number of mobile sales vehicles may be three or more. Further, while an on-board device  200  loaded on the mobile sales vehicle SA is referred to as an on-board device  200 A, and an on-board device  200  loaded on the mobile sales vehicle SB is referred to as an on-board device  200 B, the devices are simply referred to as on-board devices  200  when the devices are not distinguished or referred to by a general name. 
     For example, each of the mobile sales vehicle SA and the mobile sales vehicle SB is a mobile-type supermarket traveling in accordance with a predetermined traveling route, stopping at a predetermined location, and selling a loaded item to a customer. The mobile sales vehicle may also be referred to as a mobile supermarket. Traveling routes according to which the plurality of mobile sales vehicles (SA, SB) travel may be identical, different, or partially overlapping one another. 
     It is assumed that a user UC is a customer using a mobile sales vehicle, according to the present example embodiment. It is further assumed that a user UA living in a customer house CA is a customer doing online shopping by use of a customer terminal  300 A. It is further assumed that a user UB living in a customer house CB is a customer doing online shopping by use of a customer terminal  300 B. The customer terminal  300 A and the customer terminal  300 B are simply referred to as customer terminals  300  when the terminals are not distinguished or referred to by a general name. The customer house CA and the customer house CB may be houses facing roads on the traveling routes of the mobile sales vehicles (SA, SB) or may be houses within a predetermined range from the traveling routes, respectively. 
     A store providing a service allowing a customer to do online shopping is hereinafter referred to as an online shop. 
     The item sales system  2  according to the present example embodiment provides both a customer using a mobile sales vehicle and a customer doing online shopping with benefits of using the respective means, by the stock management device  100  communicating with an on-board device  200  and a customer terminal  300 . 
     Next, a function of each device in the item sales system  2  according to the present example embodiment will be described in detail.  FIG. 9  is a functional block diagram illustrating a functional configuration example of the stock management device  100  in the item sales system  2  according to the present example embodiment. As illustrated in  FIG. 9 , the stock management device  100  includes a management unit  110 , a first reception unit  120 , a first transmission unit  130 , a second reception unit  140 , a first transmission unit  140 , a second transmission unit  150 , a stock information storage unit  160 , and a customer information storage unit  170 . 
     The stock information storage unit  160  stores stock information being information indicating stock of items in stock held by each of a plurality of mobile sales vehicles. The stock information stored by the stock information storage unit  160  will be described with reference to  FIG. 10 .  FIG. 10  is a diagram illustrating an example of stock information stored by the stock information storage unit  160  according to the present example embodiment. The stock information includes at least an item name being information for identifying an item held by each of a plurality of mobile sales vehicles, and a quantity of an item represented by the item name for each mobile sales vehicle. The stock information may include a unit price, as illustrated in  FIG. 10 . Information included in the stock information is not limited to the above. 
     The customer information storage unit  170  stores customer information indicating information about a customer using a mobile sales vehicle and/or an online shop. The customer information stored by the customer information storage unit  170  will be described with reference to  FIG. 11 .  FIG. 11  is a diagram illustrating an example of customer information stored by the customer information storage unit  170  according to the present example embodiment. The customer information includes a customer IDentifier (ID) for identifying a customer, a name of the customer, an address of the customer, and a telephone number of the customer. The customer information is not limited to the above and may include other information. Further, the customer information has only to include information by which a delivery address of an item can be identified. Further, for example, the customer information may include authentication information used for logging into an online shop. The customer information may be pre-registered when a service provided by the item sales system  2  is used. The registration method of the customer information is not particularly limited. 
     The stock information storage unit  160  and the customer information storage unit  170  may be implemented as separate storage units or may be implemented as the same storage unit. Further, the stock information storage unit  160  and the customer information storage unit  170  may be implemented as a storage device separate from the stock management device  100 . Further, the stock information storage unit  160  and the customer information storage unit  170  may store stock information and customer information as databases, respectively. 
     The first reception unit  120  corresponds to the first reception unit  12  according to the first example embodiment. The first reception unit  120  receives from each of a plurality of mobile sales vehicles sales information indicating an item sold at its storefront. The sales information includes at least information (for example, an item name and an item identifier) for identifying an item sold at the storefront of the mobile sales vehicle and a quantity of the item. It is assumed below that the information for identifying an item is an item name. The first reception unit  120  provides the received sales information to the management unit  110  along with information (referred to as mobile sales vehicle information) indicating a mobile sales vehicle loaded with an on-board device  200  being a source of the sales information. The mobile sales vehicle information may be an identifier for identifying a mobile sales vehicle, a license plate number of the mobile sales vehicle, a vehicle identification number of the mobile sales vehicle, a model name of the mobile sales vehicle, or the like. 
     Further, the first reception unit  120  receives, from each of a plurality of mobile sales vehicles, state information indicating a state of the mobile sales vehicle. Details of the state information will be described later. The first reception unit  120  provides the received state information to the management unit  110 . 
     The second reception unit  140  corresponds to the second reception unit  14  according to the first example embodiment. The second reception unit  140  receives, from a customer terminal  300 , order information including information about an item ordered based on stock information transmitted to the customer terminal  300  and sales state information to be described later. The order information includes at least information for identifying a customer ordering an item, information (for example, an item name and an item identifier) for identifying the ordered item, the item being included in stock information managed by the management unit  110 , and a quantity of the item. The second reception unit  140  provides the received order information to the management unit  110 . The order information received by the second reception unit  140  may include delivery address information indicating a delivery address designated by a customer. 
     The management unit  110  corresponds to the management unit  11  according to the first example embodiment. The management unit  110  manages stock information stored in the stock information storage unit  160 . Further, the management unit  110  manages customer information stored in the customer information storage unit  170 . Further, the management unit  110  may manage sales information and order information. The sales information and the order information may be stored and managed in a storage unit in the stock management device  100 . 
     Information about stock items loaded on a mobile sales vehicle is registered in the stock information managed by the management unit  110  before each of a plurality of mobile sales vehicles starts mobile sale and also before the item being purchasable by online shopping. Then, the management unit  110  updates the stock information every time an item is purchased by mobile sale, every time an item is purchased by online shopping, and every time an item is carried in. 
     Further, the management unit  110  acquires, from the stock information storage unit  160 , stock information to be transmitted to a customer terminal and provides the acquired stock information to the first transmission unit  130 . At this time, the stock information acquired by the management unit  110  may be stock information about stock held by each of the mobile sales vehicles allowing a customer to purchase the items on an online shop at present, or may be stock information about stock held by mobile sales vehicles positioned within a predetermined range from a customer terminal, based on a position of the customer terminal. The mobile sales vehicle allowing a customer to purchase an item on an online shop at present refers to, for example, a mobile sales vehicle capable of selling items on a luggage carrier at present, such as a mobile sales vehicle not being back in a garage, a mobile sales vehicle not all of items running out of stock, or a mobile sales vehicle not ending sale (not on the way back to a garage). Further, the stock information acquired by the management unit  110  may be, for example, stock information about stock held by a mobile sales vehicle positioned within a predetermined range from a delivery address when the delivery address is designated by a customer terminal. Further, the stock information acquired by the management unit  110  may be stock information about stock held by a mobile sales vehicle predesignated by a customer. Thus, the stock information acquired by the management unit  110  is not particularly limited. 
     Further, the management unit  110  receives state information from the first reception unit  120 . The state information is generated based on at least one of a signal indicating a change in movement of or an operating state of a mobile sales vehicle, a signal indicating a change in an engine of the mobile sales vehicle or an operating state of the engine, and a signal indicating whether or not the mobile sales vehicle is open for business. The management unit  110  confirms whether or not the mobile sales vehicle is selling items based on the received state information. Then, the management unit  110  generates sales state information including the confirmation result (information indicating whether or not the mobile sales vehicle is selling items). For example, when state information indicates at least one state of a mobile sales vehicle being stopped, an engine of the mobile sales vehicle being stopped, and the mobile sales vehicle being open for business, the management unit  110  generates sales state information indicating that the mobile sales vehicle sells items. Further, for example, when state information indicates at least one state of a mobile sales vehicle moving, an engine of the mobile sales vehicle running, and the mobile sales vehicle being closed, the management unit  110  generates sales state information indicating that the mobile sales vehicle does not sell items. The management unit  110  provides the generated sales state information to the first transmission unit  130 . 
     Further, the management unit  110  updates stock information based on at least one of sales information and order information. For example, when sales information is transmitted from the on-board device  200  on the mobile sales vehicle SA, the management unit  110  updates stock information about stock held by the mobile sales vehicle SA, based on the sales information. Further, for example, when a mobile sales vehicle holding an item included in order information is the mobile sales vehicle SA, the management unit  110  updates stock information about stock held by the mobile sales vehicle SA, based on the order information. 
     Further, the management unit  110  provides, to the second transmission unit  150 , order information received by the second reception unit  140  along with information indicating a mobile sales vehicle holding an item included in the order information. 
     Further, when receiving sales information after the first transmission unit  130  transmits stock information to a customer terminal, the management unit  110  provides, to the first transmission unit  130 , the sales information along with an instruction to transmit sales information to the customer terminal. 
     Further, when an item of which quantity in stock becomes zero by updating stock information exists, the management unit  110  may transmit, to a mobile sales vehicle holding the item the stock quantity of which is zero sellout information indicating that the item held by the mobile sales vehicle is sold out. 
     The first transmission unit  130  corresponds to the first transmission unit  13  according to the first example embodiment. The first transmission unit  130  receives stock information from the management unit  110 . The first transmission unit  130  transmits the stock information to a customer terminal  300 . When, for example, a browser is activated by a customer terminal  300 , the first transmission unit  130  may generate a screen including stock information and transmit the generated screen to the customer terminal  300 . Further, when, for example, an application is activated by a customer terminal  300 , the first transmission unit  130  may transmit information including stock information to the customer terminal  300  in such a way that the application can display a screen including the stock information. When a customer terminal  300  can display a screen including stock information, the first transmission unit  130  may transmit stock information itself acquired by the management unit  110 . It is preferable that a timing when the first transmission unit  130  transmits stock information to a customer terminal  300  be after detecting an operation of a customer for purchasing an item by use of the customer terminal  300 . Detecting an operation of a customer for purchasing an item by use of a customer terminal  300  includes, for example, detecting, by a customer inputting login information to a customer terminal  300  for logging into an online shop, reception of the login information from the customer terminal  300  by the stock management device  100 . Consequently, the customer using the customer terminal  300  can confirm stock information at a timing of logging into the online shop. 
     Further, the first transmission unit  130  may further transmit the updated stock information to a customer terminal  300  every time stock information is updated. Consequently, a customer using the customer terminal  300  can confirm latest stock information at updating. 
     Further, when receiving sales state information from the management unit  110 , the first transmission unit  130  transmits the sales state information to a customer terminal  300 . Further, when receiving sales information from the management unit  110 , the first transmission unit  130  transmits the sales information to the customer terminal. The first transmission unit  130  may transmit the sales state information along with the stock information to the customer terminal  300 . 
     The second transmission unit  150  corresponds to the second transmission unit  15  according to the first example embodiment. The second transmission unit  150  transmits order information to a mobile sales vehicle holding an ordered item included in the order information. 
     Next, a functional configuration of an on-board device  200  will be described with reference to  FIG. 12 .  FIG. 12  is a functional block diagram illustrating a functional configuration example of an on-board device  200  in the item sales system  2  according to the present example embodiment. The on-board device  200  includes a sales information acceptance unit  210 , a transmission unit  220 , a detection unit  230 , and a reception unit  240 . 
     The sales information acceptance unit  210  accepts sales information including an item name of an item sold by a mobile sale (an item purchased by a customer) of a mobile sales vehicle loaded with the on-board device  200 , and a quantity of the item. For example, the sales information acceptance unit  210  is implemented with a point of sales (POS) register. The sales information acceptance unit  210  provides the accepted sales information to the transmission unit  220 . 
     The detection unit  230  detects a state change of or an operating state of a mobile sales vehicle loaded with an on-board device  200 . Based on the detection result, the detection unit  230  generates state information indicating a state of the mobile sales vehicle. The detection unit  230  generates state information, for example, based on at least one of a signal indicating a change in movement of or an operating state of a mobile sales vehicle, a signal indicating a change in an engine of the mobile sales vehicle or an operating state of the engine, and a signal indicating whether or not the mobile sales vehicle is open for business. 
     For example, triggered by a state information transmission request being transmitted from the stock management device  100 , the detection unit  230  detects an operating state of a mobile sales vehicle at that time and generates the detection result as state information. Further, the detection unit  230  may, for example, detect an operating state of a mobile sales vehicle at that time at predetermined intervals and generate the detection result as state information. 
     Further, for example, the detection unit  230  detects signals indicating a mobile sales vehicle starting to move from a stopped state and the mobile sales vehicle stopping from a moving state. Further, for example, the detection unit  230  detects a signal indicating an engine of a mobile sales vehicle stopping or the engine of the mobile sales vehicle being activated. Then, the detection unit  230  generates state information, based on the detection result. 
     Further, for example, the detection unit  230  detects a signal indicating a start of sale of an item or an end of sale of an item at a mobile sales vehicle. Specifically, for example, by detecting a signal indicating that a luggage carrier is opened or detecting a signal indicating that a POS register is opened, the detection unit  230  determines that a signal indicating a start of sale of an item at the mobile sales vehicle is detected. Further, for example, by detecting a signal indicating that a luggage carrier is closed or detecting a signal indicating that a POS register is closed, the detection unit  230  determines that a signal indicating an end of sale of an item at the mobile sales vehicle is detected. 
     Then, the detection unit  230  provides, to the transmission unit  220 , state information indicating a 0045 state of the mobile sales vehicle, the state information being generated based on the detection result. 
     For example, when a state change detected by the detection unit  230  indicates a mobile sales vehicle starting to move from stopped state, the state change tells that a current state is moving. Accordingly, the detection unit  230  generates state information indicating the mobile sales vehicle moving and provides the state information to the transmission unit  220 . Further, for example, when a state change detected by the detection unit  230  indicates a mobile sales vehicle stopping from a moving state, the detection unit  230  generates state information indicating the mobile sales vehicle stopped and provides the state information to the transmission unit  220 . Further, for example, when a state change detected by the detection unit  230  indicates an engine of a mobile sales vehicle being stopped, the detection unit  230  generates state information indicating the engine being stopped and provides the state information to the transmission unit  220 . Further, for example, when a state change detected by the detection unit  230  indicates an engine of a mobile sales vehicle being activated, the detection unit  230  generates state information indicating the engine running and provides the state information to the transmission unit  220 . Further, for example, when a state change detected by the detection unit  230  indicates selling of an item being started at a mobile sales vehicle, the detection unit  230  generates state information indicating open for business and provides the state information to the transmission unit  220 . Further, for example, when a state change detected by the detection unit  230  indicates selling of an item ending at a mobile sales vehicle, the detection unit  230  generates state information indicating closed and provides the state information to the transmission unit  220 . A state change detected by the detection unit  230  is not limited to the above. Further, for example, state information may be positional information. 
     When receiving sales information from the sales information acceptance unit  210 , the transmission unit  220  transmits the sales information to the stock management device  100 . Further, when receiving state information from the detection unit  230 , the transmission unit  220  transmits the state information to the stock management device  100 . 
     The reception unit  240  receives order information transmitted from the stock management device  100 . Consequently, a mobile sales vehicle loaded with the on-board device  200  receiving the order information can deliver an ordered item to a delivery address indicated by delivery address information, based on the order information. 
     Further, when sellout information is transmitted from the stock management device  100 , the reception unit  240  may receive the sellout information. Consequently, a driver of a mobile sales vehicle loaded with the on-board device  200  or a customer using the mobile sales vehicle can understand that an item indicated by the sellout information is sold out. 
     Next, a functional configuration of a customer terminal  300  will be described with reference to  FIG. 13 .  FIG. 13  is a functional block diagram illustrating a functional configuration example of a customer terminal  300  in the item sales system  2  according to the present example embodiment. As illustrated in  FIG. 13 , the customer terminal  300  includes a reception unit  310 , a control unit (display control unit)  320 , a display unit  330 , an acceptance unit  340 , and a transmission unit  350 . 
     The reception unit  310  corresponds to the reception unit  31  according to the first example embodiment. The reception unit  310  receives stock information from the stock management device  100 . The stock information has only to include information required for displaying information about stock of an item held by a mobile sales vehicle on the display unit  330  and may be, for example, the stock information itself stored in the stock information storage unit  160 , part of the stock information, or processed stock information. The reception unit  310  provides the received stock information to the control unit  320 . 
     Further, the reception unit  310  receives sales state information from the stock management device  100 . The reception unit  310  provides the received sales state information to the control unit  320 . The reception unit  310  may receive the sales state information along with the stock information. 
     Further, the reception unit  310  receives sales information from the stock management device  100 . The reception unit  310  provides the received sales information to the control unit  320 . 
     The display unit  330  displays a screen in accordance with an instruction by the control unit  320 . For example, the display unit  330  is implemented with a liquid crystal display. The display unit  330  may be implemented with a display device separate from the customer terminal  300 . 
     The acceptance unit  340  accepts an instruction from a user using the customer terminal  300 . For example, the acceptance unit  340  accepts an instruction from a user input through an input device such as a mouse or a keyboard. The acceptance unit  340  provides the accepted instruction to the control unit  320 . 
     The acceptance unit  340  and the display unit  330  may be integrally formed as a touch panel. 
     The control unit  320  corresponds to the display control unit  32  according to the first example embodiment. The control unit  320  controls the display unit  330  to display a screen based on the stock information and the sales state information that are received by the reception unit  310 . When the sales state information indicates that a mobile sales vehicle sells items at its storefront, the control unit  320  may control the display unit  330  to display an item included in stock information related to the mobile sales vehicle in a mode different from an item included in stock information related to another mobile sales vehicle. Further, the control unit  320  provides, to the transmission unit  350 , the order information including information about an item ordered by a customer. 
     Further, when receiving sales information from the reception unit  310 , the control unit  320  causes the display unit  330  to display a screen based on the sales information. The screen will be described later by another drawing. 
     When receiving order information from the control unit  320 , the transmission unit  350  transmits the order information to the stock management device  100 . 
     Next, processing of updating stock information, based on sales information, in the item sales system  2  will be described with reference to  FIG. 14 .  FIG. 14  is a flowchart illustrating an example of a flow of the processing of updating stock information, based on sales information, in the item sales system  2  according to the present example embodiment. 
     It is assumed in  FIG. 14  that the management unit  110  in the stock management device  100  manages stock information about stock of an item held by a plurality of mobile sales vehicles, for each mobile sales vehicle. Further, in  FIG. 14 , processing by an on-board device  200  is described on the left and processing by the stock management device  100  on the right; and a broken arrow between the respective processing steps represents a flow of primary information. An information flow is not limited to a direction of an arrow, and for example, an ACK may be transmitted in a direction reverse to the arrow. 
     First, by a mobile sales vehicle loaded with the on-board device  200  conducting mobile sale, the sales information acceptance unit  210  in the on-board device  200  accepts sales information including an item name of a sold item (an item purchased by a customer) and a quantity of the item (Step S 141 ). Then, the transmission unit  220  transmits the sales information to the stock management device  100  (Step S 142 ). 
     The first reception unit  120  in the stock management device  100  receives the sales information transmitted from the on-board device  200  (Step S 143 ). The first reception unit  120  provides the sales information to the management unit  110  along with mobile sales vehicle information. 
     Based on the sales information provided from the first reception unit  120 , the management unit  110  updates stock information about stock held by a mobile sales vehicle specified by the mobile sales vehicle information transmitted along with the sales information (Step S 144 ). 
     The above concludes the processing of updating stock information, based on sales information. 
     Next, transmission processing of state information by an on-board device  200  will be described with reference to  FIG. 15 .  FIG. 15  is a flowchart illustrating an example of a flow of the transmission processing of state information by an on-board device  200  in the item sales system  2  according to the present example embodiment. The processing illustrated in  FIG. 15  is performed asynchronously with the processing of updating stock information illustrated in  FIG. 14 . 
     As described in  FIG. 15 , the detection unit  230  detects a state change of or an operating state of a mobile sales vehicle (Step S 151 ). Based on the detection result, the detection unit  230  generates state information about the mobile sales vehicle at the time of the detection and provides the state information to the transmission unit  220 . Then, the transmission unit  220  transmits the state information to the stock management device  100  (Step S 152 ). 
     The above concludes the transmission processing of state information by an on-board device  200 . 
     Next, sales processing of an item by online shopping in the item sales system  2  will be described with reference to  FIGS. 16 and 17 .  FIGS. 16 and 17  are flowcharts illustrating an example of a flow of the sales processing of an item by online shopping in the item sales system  2  according to the present example embodiment. The processing illustrated in  FIGS. 16 and 17  is performed asynchronously with the processing of updating stock information illustrated in  FIG. 14  and the transmission processing of state information illustrated in  FIG. 15 . 
     In  FIGS. 16 and 17 , processing by a customer terminal  300  is indicated on the left, and processing by the stock management device  100  on the right. Further, a broken arrow between the respective processing steps in  FIGS. 16 and 17  represents a flow of primary information. An information flow is not limited to a direction of an arrow, and for example, an ACK may be transmitted in a direction reverse to the arrow. 
     A user (customer) using a customer terminal  300  inputs an instruction to start online shopping into the customer terminal  300 , and the acceptance unit  340  accepts a content of the instruction. For example, when an instruction to activate a browser is input in order to do online shopping, the control unit  320  activates the browser (Step S 161 ). For example, when processing accepted by the acceptance unit  340  is an instruction to activate an application for doing online shopping, the control unit  320  activates the application installed on the customer terminal  300 . 
     Then, the transmission unit  350  transmits information required for doing online shopping to the stock management device  100 . For example, the transmission unit  350  transmits to the stock management device  100  login information, such as a customer ID and authentication information for logging into an online shop (Step S 162 ). The login information may be input by a customer for each shopping. 
     When receiving the login information transmitted from the customer terminal  300  (Step S 163 ), the second reception unit  140  in the stock management device  100  transmits the login information to the management unit  110 . Then, the management unit  110  refers to the customer information storage unit  170  and performs user authentication (Step S 164 ). The user authentication may use any method, and therefore description is omitted in the present example embodiment. 
     Subsequently, when the customer is authenticated, the management unit  110  acquires stock information stored in the stock information storage unit  160  and provides the acquired stock information to the first transmission unit  130 . Further, when state information is received from an on-board device  200 , the management unit  110  confirms whether or not a mobile sales vehicle from which the state information is received is selling items, based on the state information. Then, the management unit  110  generates sales state information indicating whether or not the mobile sales vehicle is selling items (Step S 165 ). Then, the first transmission unit  130  transmits the sales state information along with the stock information acquired by the management unit  110  to the customer terminal  300  transmitting the login information to the stock management device  100  (Step S 166 ). For example, it is assumed that the stock information includes information about stock held by the mobile sales vehicle SA and information about stock held by the mobile sales vehicle SB, as illustrated in  FIG. 10 , and only the mobile sales vehicle SA sells items at its storefront. In this case, the first transmission unit  130  transmits, to the customer terminal  300 , stock information, and sales state information indicating that the mobile sales vehicle SA sells items and the mobile sales vehicle SB does not sell items. As described above, the first transmission unit  130  may transmit the stock information and the sales state information separately to the customer terminal  300 . It is assumed in the following description that stock information and sales state information are transmitted to the customer terminal  300  from the first transmission unit  130 . Further, a timing of transmission of the stock information by the first transmission unit  130  may be after the stock management device  100  receives a transmission instruction of the stock information from the customer terminal subsequently to performing the user authentication. The timing of transmission of the stock information by the first transmission unit  130  has only to be after detection of the customer starting shopping on an online shop by use of the customer terminal  300  (performing an operation for purchasing an item by use of the customer terminal  300 ) such as after the stock management device  100  receives the aforementioned transmission instruction of stock information. Further, the item sales system  2  may be configured not to perform user authentication. 
     Then, the reception unit  310  in the customer terminal  300  receives the stock information and the sales state information from the stock management device  100  (Step S 167 ). Subsequently, the control unit  320  causes the display unit  330  to display a screen based on the received stock information and the sales state information (Step S 168 ). 
     A screen (ordering screen) based on stock information and sales state information, the screen being displayed by the display unit  330 , will be described with reference to  FIG. 18 .  FIG. 18  is a diagram illustrating an example of an ordering screen displayed by the display unit  330  in a customer terminal  300  according to the present example embodiment. 
     It is assumed in the example in  FIG. 18  that stock information about stock held by the mobile sales vehicle SA and about stock held by the mobile sales vehicle SB is transmitted to the customer terminal  300  from the stock management device  100 . It is further assumed that the reception unit  310  receives sales state information indicating the mobile sales vehicle SA sells items and indicating the mobile sales vehicle SB does not sell items. 
     The ordering screen illustrated in  FIG. 18  displays information about items, a total stock quantity of each of which held by the mobile sales vehicle SA and held by the mobile sales vehicle SB being one or more, out of the stock information illustrated in  FIG. 10 . Further, since the mobile sales vehicle SA is selling items at its storefront, “ON SALE AT STOREFRONT” indicating that an item is being sold at the storefront is displayed for an item held by the mobile sales vehicle SA. Specifically, “ON SALE AT STOREFRONT” is displayed for an item with an item name other than “PEAR” and “BAUMKUCHEN.” Thus, the control unit  320  causes the display unit  330  to display a screen (ordering screen) based on stock information and sales state information. 
     An “ADD TO CART” button in  FIG. 18  is a button for accepting an instruction to add a relevant item to a cart on an online shop. In accordance with the instruction, the control unit  320  keeps information about the item added to the cart as cart information. The cart information includes information for identifying an item and a quantity of the item. 
     A “PROCEED TO ORDERED ITEMS CONFIRMATION SCREEN” button in  FIG. 18  is a button for transition to a screen for confirming an item ordered by a customer. On the ordered items confirmation screen, a list of items added to the cart is displayed. Details of the ordered items confirmation screen will be described later. While the ordered items confirmation screen will be described as being displayed on a screen separate from the ordering screen in  FIG. 18 , the ordered items confirmation screen and the ordering screen may be displayed in separate frames on the same browser. Display forms of the ordering screen and the ordered items confirmation screen are not particularly limited. 
       FIG. 19  is a diagram illustrating another example of an ordering screen displayed by the display unit  330  in the customer terminal  300  according to the present example embodiment. In  FIG. 19 , an item other than an item held by the mobile sales vehicle SA is displayed in boldface type. Thus, the customer terminal  300  displays an item being sold at a storefront differently from an item not being sold at a storefront. As described above, based on sales state information, the control unit  320  may express an item being sold at a storefront by displaying a character string such as “ON SALE AT STOREFRONT” as illustrated in  FIG. 18  or may express a relevant item in a different manner from another item as illustrated in  FIG. 19 . For example, the control unit  320  may cause an item name of an item being sold at a storefront to blink, to be displayed in a color different from another character, or to be displayed in a font smaller than another character. 
     The control unit  320  may further get a quantity of an item being sold at a storefront displayed on the ordering screen. For example, “APPLE” is designated being sold at a storefront in  FIG. 18 . The quantity of apples being sold at the storefront is five which is held by the mobile sales vehicle SA. Accordingly, for example, the control unit  320  may get “5 ON SALE AT STOREFRONT” displayed on the ordering screen. 
     Thus, when sales state information indicates that the mobile sales vehicle SA is selling items at its storefront, the control unit  320  gets an item included in stock information related to the mobile sales vehicle SA displayed on the ordering screen in a different manner from an item included in stock information related only to the mobile sales vehicle SB. Consequently, the customer terminal  300  enables a customer ordering an item by use of the ordering screen to readily understand sales status of the item at a mobile sales vehicle. 
     Returning to the flow in  FIG. 16 , processing after Step S 168  will be described. The first reception unit  120  in the stock management device  100  confirms whether or not state information is received from the on-board device  200  (Step S 169 ), and when state information is not received (NO in Step S 169 ), advances the processing to Step S 176 . When state information is received (YES in Step S 169 ), the management unit  110  generates sales state information based on the state information (Step S 170 ). Then, the first transmission unit  130  transmits the sales state information to the customer terminal  300  (Step S 171 ). 
     Then, the reception unit  310  in the customer terminal  300  receives the sales state information (Step S 172 ). Then, the control unit  320  causes the display unit  330  to display an ordering screen updated from the ordering screen displayed by the display unit  330  in Step S 168 , based on the sales state information (Step S 173 ). For example, a case that the display unit  330  displays an ordering screen indicating the mobile sales vehicle SA is selling items as illustrated in  FIG. 18  and the sales state information received in Step S 172  indicates the mobile sales vehicle SA is not selling items at its storefront will be described. In this case, the control unit  320  causes the display unit  330  to display an ordering screen with the character string “ON SALE AT STOREFRONT” illustrated in  FIG. 18  deleted. When the stock management device  100  does not receive state information, the customer terminal  300  skips the processing in Steps S 172  and S 173 . Processing in and after Step S 173  will be described with reference to  FIG. 17 . 
     Subsequently, by use of a screen (ordering screen) displayed based on the stock information and the sales state information, the customer orders an item. For example, when the customer depresses an “ADD TO CART” button illustrated in  FIG. 18 , the customer terminal  300  receives an order for an item by the customer, by the acceptance unit  340  accepting the depression of the button (Step S 174 ). Subsequently, for example, when the “PROCEED TO ORDERED ITEMSCONFIRMATION SCREEN” button illustrated in  FIG. 18  is depressed by the customer, the customer terminal  300  determines that an instruction to end the shopping is accepted, by the acceptance unit  340  accepting the depression of the button (YES in Step S 175 ). The customer terminal  300  repeats Steps S 174  and S 175  until the acceptance unit  340  accepts the instruction to end the shopping. 
     Further, the first reception unit  120  in the stock management device  100  confirms whether or not sales information is received from the on-board device  200  (Step S 176 ), and when sales information is not received (NO in Step S 176 ), advances the processing to Step S 182 . When sales information is received (YES in Step S 176 ), the first transmission unit  130  transmits the sales information to the customer terminal  300  (Step S 177 ). 
     The reception unit  310  in the customer terminal  300  confirms whether or not sales information is received from the stock management device  100  (Step S 178 ). When sales information is not received (NO in Step S 178 ), the reception unit  310  advances the processing to Step S 180 . When sales information is received (YES in Step S 178 ), the control unit  320  causes the display unit  330  to display a screen based on the sales information (Step S 179 ). The screen (confirmation screen) based on the sales information, the control unit  320  causing the display unit  330  to display the screen in Step S 179 , will be described with reference to  FIG. 20 . For example, it is assumed that the customer adds “VEGETABLE JUICE (200 ML)” to the cart on the ordering screen illustrated in  FIG. 18  and depresses “PROCEED TO ORDERED ITEMS CONFIRMATION SCREEN.” Then, it is assumed that the sales information received in Step S 178  includes information indicating that all 10 each of “VEGETABLE JUICE (200 ML)” are purchased at a mobile sales vehicle. In this case, the stock has become zero during a period from a time when the ordering screen is displayed to a time when “PROCEED TO ORDERED ITEMS CONFIRMATION SCREEN” is depressed, and therefore the customer using the customer terminal  300  cannot purchase the “VEGETABLE JUICE (200 ML).” Accordingly, for example, the control unit  320  causes the display unit  330  to display a confirmation screen as illustrated in  FIG. 20 . Consequently, the customer terminal  300  enables the customer to understand that an item put into the cart by the customer is not purchasable. For example, the confirmation screen illustrated in  FIG. 20  may be pop-up. 
     Subsequently, the control unit  320  causes the display unit  330  to display an ordered items confirmation screen (Step S 180 ). The ordered items confirmation screen which the control unit  320  causes the display unit  330  to display in Step S 180  will be described with reference to  FIG. 21 . For example, it is assumed that the customer adds “APPLE” and “TOMATO” to the cart on the ordering screen illustrated in  FIG. 18 . Based on kept cart information, the control unit  320  displays the ordered items confirmation screen. For example, a case that the customer adds “APPLE,” “TOMATO,” and “VEGETABLE JUICE (200 ML)” to the cart on the ordering screen illustrated in  FIG. 18 , and “VEGETABLE JUICE (200 ML)” is not purchasable is assumed. In this case, after displaying the confirmation screen in  FIG. 20 , the control unit  320  may display, on the display unit  330 , an ordered items confirmation screen displaying only a purchasable item. 
     Further, in the case described above, after displaying or not displaying the confirmation screen in  FIG. 20 , the control unit  320  may display an ordered items confirmation screen as illustrated in  FIG. 22  on the display unit  330 . The ordered items confirmation screen illustrated in  FIG. 22  includes information about an item becoming sold out, based on sales information. 
     A “PROCEED TO PAYMENT SCREEN” button in  FIGS. 21 and 22  is a button for transition to a screen for making payment. A payment method can be selected on the payment screen. The payment method is not particularly limited, and therefore description is omitted in the present example embodiment. When an instruction to make payment is input, the acceptance unit  340  accepts the instruction. Then, in accordance with the instruction to make payment, the control unit  320  provides information (information about an item included in the ordered items confirmation screen) kept as cart information and information for identifying the customer to the transmission unit  350  as order information. Subsequently, the transmission unit  350  transmits the order information to the stock management device  100  (Step S 181 ). 
     The second reception unit  140  in the stock management device  100  determines whether or not order information is received from the customer terminal  300  (Step S 182 ). When order information is not received (NO in Step S 182 ), the stock management device  100  returns the processing to Step S 169  and repeats Steps S 169  to S 171 , S 176 , and S 177  until order information is received. 
     When order information is received (YES in Step S 182 ), the second transmission unit  150  transmits the order information to a mobile sales vehicle holding an item included in the order information and delivering the item, based on the order information received by the second reception unit  140  (Step S 183 ). Further, the management unit  110  updates the stock information based on the order information (Step S 184 ). Step S 183  may be performed before Step S 184  or may be performed at a time with Step S 184 . 
     Since the reception unit  240  in the on-board device  200  receives the order information transmitted from the stock management device  100  by Step S 183  being performed, a mobile sales vehicle loaded with the on-board device  200  can deliver the item to the customer, based on the order information. 
     The above concludes the sales processing of an item by online shopping, by the item sales system  2 . 
     As described above, the management unit  110  in the stock management device  100  in the item sales system  2  according to the present example embodiment manages stock information about items held by each of a plurality of mobile sales vehicles. Further, the first reception unit  120  receives sales information indicating an item sold at the mobile sales vehicle from an on-board device  200  loaded on each of the plurality of mobile sales vehicles. Further, the first reception unit  120  receives state information indicating a state of a mobile sales vehicle from an on-board device  200  loaded on each of the plurality of mobile sales vehicles. Further, the second reception unit  140  receives, from a customer terminal  300 , order information including information about an item ordered based on stock information transmitted to the customer terminal  300 . Additionally, the second transmission unit  150  transmits order information to an on-board device  200  loaded on a mobile sales vehicle holding the ordered item included in the order information. Consequently, the mobile sales vehicle loaded with the on-board device  200  receiving the order information can deliver the ordered item to a customer ordering the item. 
     Further, the stock management device  100  transmits stock information and sales state information to a customer terminal  300 . Consequently, a customer using the customer terminal  300  can place an order, based on the stock information and the sales state information. Consequently, the customer can do online shopping while, for example, understanding whether or not items of which the customer desires to purchase are being also sold at a storefront of the mobile sales vehicle at that point. 
     Further, since an on-board device  200  receives order information, a driver of a mobile sales vehicle loaded with the on-board device  200  can understand items available for actual sale out of items held by the mobile sales vehicle. 
     Accordingly, the item sales system  2  according to the present example embodiment enables a customer purchasing an item by online shopping to understand sales status of the item at a mobile sales vehicle and also to have both a benefit of online shopping and a benefit of using a mobile sales vehicle. 
     An on-board device  200  according to the present example embodiment may have a function of measuring a current position of a mobile sales vehicle loaded with the on-board device  200 . Specifically, for example, an on-board device  200  may receive positional information by use of the Global Positioning System (GPS) and measure, from the received positional information, a current position of a mobile sales vehicle loaded with the on-board device  200 . Then, the on-board device  200  may transmit, to the stock management device  100 , information (current position information) indicating a current position being the positioning result. 
     Then, the stock management device  100  may have a function of receiving current position information and specifying a mobile sales vehicle delivering an item by use of the current position information. For example, based on order information received by the second reception unit  140 , the stock management device  100  determines a candidate of a mobile sales vehicle (referred to as a delivery vehicle) delivering an item included in the order information. Then, based on a current position of a mobile sales vehicle, the current position being indicated by the current position information, and a position of a delivery address indicated by delivery address information included in the order information, the stock management device  100  may specify a mobile sales vehicle arriving earliest at the delivery address, from mobile sales vehicles holding the ordered item, out of the determined candidates. At this time, the stock management device  100  may specify the delivery vehicle in consideration of information indicating whether or not a mobile sales vehicle is open for business, a storefront sales schedule, scheduled traveling route information, or the like. A mobile sales vehicle being open for business represents a state in which a mobile sales vehicle stops at a predetermined location, a luggage carrier is opened, and an item loaded on the mobile sales vehicle is ready to be sold to a customer. For example, the information indicating whether or not a mobile sales vehicle is open for business may be based on a signal indicating that a luggage carrier of the mobile sales vehicle is opened, the signal being transmitted from an on-board device  200  to the stock management device  100 . Further, a storefront sales schedule indicates where and when a mobile sales vehicle is scheduled to perform mobile sale. The storefront sales schedule may be stored inside the stock management device  100  or may be transmitted from an on-board device  200 . Further, scheduled traveling route information is information indicating a route on which a mobile sales vehicle is scheduled to travel. The scheduled traveling route information may be stored inside the stock management device  100  or may be transmitted from an on-board device  200 . Further, the stock management device  100  may specify the delivery vehicle in consideration of a traveling direction of a mobile sales vehicle, road information at that point in time, and the like. The traveling direction of a mobile sales vehicle and the road information may be transmitted from an on-board device  200 . The road information may be information indicating a traffic jam or information preset to a road such as one-way traffic. Further, the road information may be transmitted from an external server managing road information. Consequently, a mobile sales vehicle loaded with an on-board device  200  receiving order information becomes a mobile sales vehicle arriving earliest at a delivery address. Accordingly, an ordered item can be delivered more quickly to a customer doing online shopping. 
     Third Example Embodiment 
     Next, a third example embodiment of the present disclosure will be described. A configuration of the on-board device  200  further including a function of recognizing an item of which a customer is considering purchase will be described in the present example embodiment. 
       FIG. 23  is a diagram illustrating a functional configuration example of an on-board device  201  according to the present example embodiment. An item sales system  2  including the on-board device  201  includes the on-board device  201  in place of the on-board device  200  in the item sales system  2  illustrated in  FIG. 5 . Note that, for convenience of description, a component having the same function as that of a component included in the drawing described in the aforementioned second example embodiment is given the same reference sign, and description thereof is omitted. 
     As illustrated in  FIG. 23 , the on-board device  201  includes a sales information acceptance unit  210 , a transmission unit  221 , a detection unit  230 , a reception unit  240 , an imaging unit  251 , and a recognition unit  261 . 
     The imaging unit  251  captures a state of a storefront of a mobile sales vehicle. For example, the imaging unit  251  is implemented with an imaging device such as a surveillance camera or a web camera. The imaging unit  251  provides the captured image being captured to the recognition unit  261 . The imaging unit  251  may be implemented with an imaging device separate from the on-board device  201 . 
     The recognition unit  261  recognizes an item of which a customer using a mobile sales vehicle is considering purchase, from a captured image provided from the imaging unit  251 . For example, when a customer takes an item in hand, in order to purchase the item, from a shelf displaying items, the recognition unit  261  recognizes the item taken in the customer&#39;s hand, from a captured image. Further, when a customer puts an item into a shopping basket, the recognition unit  261  recognizes the item put into the shopping basket by the customer, from a captured image capturing a content of the shopping basket. 
     The method of recognizing an item by the recognition unit  261  is not limited to the above, and another method may be adopted. For example, when the on-board device  201  includes, in place of the imaging unit  251 , a sensor detecting that an item is taken out, the sensor being installed on a shelf displaying items, the recognition unit  261  may recognize the item being taken out, based on a detection result of the sensor. 
     The recognition unit  261  transmits a recognition result to the transmission unit  221 . 
     In addition to the function of the aforementioned transmission unit  220 , the transmission unit  221  transmits, to the stock management device  100 , a recognition result provided from the recognition unit  261  as item information indicating an item of which a customer using the mobile sales vehicle is considering purchase. 
     The stock management device  100  receiving the item information transmits the item information to a customer terminal  300  to which stock information is transmitted. Then, the reception unit  310  in the customer terminal  300  receives the item information from the stock management device  100 . The control unit  320  controls to display the display unit  330  in an understandable manner for a customer that an item indicated by the item information is likely to be purchased at the storefront of the mobile sales vehicle. 
     An example of an ordering screen displayed by the display unit  330  will be described with reference to  FIG. 24 . For example, it is assumed that a customer using a mobile sales vehicle takes an “APPLE” in hand at a storefront of the mobile sales vehicle, and item information includes information indicating the “APPLE”. 
     In this case, the control unit  320  controls the display unit  330  to display the ordering screen in an understandable manner for a customer that the “APPLE” is likely to be purchased at the storefront of the mobile sales vehicle. For example, as illustrated in  FIG. 24 , the control unit  320  gets an alert AL displayed in a column “ALERT” associated with “APPLE.” 
     Consequently, the customer terminal  300  enables the customer to understand that the “APPLE” is likely to be purchased at the storefront of the mobile sales vehicle. 
     Further, for example, it is assumed that, in a case that item information includes information indicating “APPLE”, a customer doing online shopping puts “APPLE” into a cart on the ordering screen illustrated in  FIG. 18 . At this time, for example, by displaying a pop-up confirmation screen as illustrated in  FIG. 25 , the control unit  320  enables the customer to understand that the “APPLE” put into the cart is likely to be purchased at the storefront of the mobile sales vehicle. 
       FIG. 26  is a flowchart illustrating an example of a processing flow related to item information in the item sales system  2  according to the present example embodiment. In  FIG. 26 , processing by an on-board device  201  is described on the left, processing by the stock management device  100  at the center, and processing by a customer terminal  300  on the right; and a broken arrow between the respective processing steps represents a flow of primary information. An information flow is not limited to a direction of an arrow, and for example, an ACK may be transmitted in a direction reverse to the arrow. 
     First, the imaging unit  251  in an on-board device  201  captures a state of a storefront of a mobile sales vehicle (Step S 261 ). Then, from the captured image provided from the imaging unit  251 , the recognition unit  261  recognizes an item of which a customer using the mobile sales vehicle is considering purchase (Step S 262 ). Then, based on the recognition result, the transmission unit  221  transmits item information indicating the recognized item to the stock management device  100  (Step S 263 ). The recognized item is an item of which the customer using the mobile sales vehicle is considering purchase. 
     Then, the first reception unit  120  in the stock management device  100  receives the item information from the on-board device  201  (Step S 264 ). Then, the first transmission unit  130  transmits the item information to a customer terminal  300  to which stock information is transmitted (Step S 265 ). 
     The reception unit  310  in the customer terminal  300  receives the item information from the stock management device  100  (Step S 266 ). The control unit  320  causes the display unit  330  to display a screen based on the item information (Step S 267 ). The screen displayed by the display unit  330  is displayed in an understandable manner for a customer that an item indicated by the item information is likely to be purchased at the storefront of the mobile sales vehicle. 
     Thus, by the control unit  320  controls to display the ordering screen in an understandable manner for a customer that an item indicated by the item information is likely to be purchased at the storefront of the mobile sales vehicle, a customer doing online shopping can more accurately understand sales status of the item at a mobile sales vehicle. 
     Modified Example 
     While performing recognition of an item on the on-board device  201  side has been described in the aforementioned third example embodiment, recognition of an item may be performed in the stock management device  100 .  FIG. 27  is a diagram illustrating a functional configuration example of a stock management device  101  according to this modified example. An item sales system  2  including the stock management device  101  includes the stock management device  101  in place of the stock management device  100  in the item sales system  2  illustrated in  FIG. 5 . Note that, for convenience of description, a component having the same function as that of a component included in the drawing described in the aforementioned second example embodiment is given the same reference sign, and description thereof is omitted. 
     As illustrated in  FIG. 27 , the stock management device  101  according to this modified example includes a management unit  110 , a first reception unit  121 , a first transmission unit  131 , a second reception unit  140 , a second transmission unit  150 , a stock information storage unit  160 , a customer information storage unit  170 , and a recognition unit  181 . 
     The first reception unit  121  includes the function of the aforementioned first reception unit  120 . Further, the first reception unit  121  receives, from a mobile sales vehicle, a captured image capturing a state of a storefront of the mobile sales vehicle. Then, the first reception unit  121  provides the received captured image to the recognition unit  181 . 
     The recognition unit  181  receives a captured image from the first reception unit  121 . The recognition unit  181  recognizes an item of which a customer using a mobile sales vehicle is considering purchase, from the received captured image. The recognition unit  181  provides the recognition result to the first transmission unit  131 . 
     The first transmission unit  131  receives a recognition result from the recognition unit  181 . The recognition result includes information about an item of which a customer of a mobile sales vehicle is considering purchase. The first transmission unit  131  transmits, to a customer terminal, item information indicating a recognized item, the item information being included in the recognition result. 
     Consequently, the control unit  320  in the customer terminal  300  receiving the item information can cause the display unit  330  to display a screen based on the item information. Consequently, the item sales system  2  including the stock management device  101  according to this modified example can also enable a customer doing online shopping to more accurately understand sales status of an item at a mobile sales vehicle, similarly to the third example embodiment. 
     About Hardware Configuration 
     Each component in each of the stock management device, the on-board device, and the customer terminal, according to the respective example embodiments of the present disclosure, represents a functional unit block. For example, each component in each of the stock management device, the on-board device, and the customer terminal is implemented in part or in whole with any combination of an information processing device  900  as illustrated in  FIG. 28  and a program.  FIG. 28  is a block diagram illustrating a hardware configuration example of the information processing device  900  implementing each component in each of the stock management device, the on-board device, and the customer terminal. As an example, the information processing device  900  includes a configuration as described below.
         A central processing unit (CPU)  901     A read only memory (ROM)  902     A random access memory (RAM)  903     A program  904  loaded into the RAM  903     A storage device  905  storing the program  904     A drive device  907  performing reading from and writing to a recording medium  906     A communication interface  908  connected to a communication network  909     An input-output interface  910  performing input and output of data   A bus  911  connecting the respective components       

     Each component in each of the stock management device, the on-board device, and the customer terminal, according to the respective example embodiments, is implemented by the CPU  901  acquiring and executing the program  904  implementing a function of the component. For example, the program  904  implementing the function of each component in each of the stock management device, the on-board device, and the customer terminal is pre-stored in the storage device  905  or the ROM  902 , and is read by the CPU  901  as needed. The program  904  may be provided to the CPU  901  through the communication network  909 ; or the program may be pre-stored in the recording medium  906 , and the drive device  907  may read the program and provide the program to the CPU  901 . 
     There are various modified examples of the implementation method of each of the stock management device, the on-board device, and the customer terminal. For example, each of the stock management device, the on-board device, and the customer terminal may be implemented with any combination of a separate information processing device  900  and a program, for each component. Further, a plurality of components included in each of the stock management device, the on-board device, and the customer terminal may be implemented with any combination of a single information processing device  900  and a program. 
     Further, each component in each of the stock management device, the on-board device, and the customer terminal is implemented in part or in whole with another general-purpose or dedicated circuit, a processor, or the like, or a combination thereof. The above may be configured with a single chip or may be configured with a plurality of chips connected through a bus. 
     Each component in each of the stock management device, the on-board device, and the customer terminal may be implemented in part or in whole with a combination of the aforementioned circuit or the like, and a program. 
     When each component in each of the stock management device, the on-board device, and the customer terminal is implemented in part or in whole with a plurality of information processing devices, circuits, or the like, the plurality of information processing devices, circuits, or the like may be arranged in a concentrated manner or be arranged in a distributed manner. For example, the information processing devices, the circuits, or the like may be implemented in a form of being connected to one another through a communication network, such as a client-server system, a cloud computing system, or the like. 
     The respective aforementioned example embodiments are preferred example embodiments of the present disclosure, and the scope of the present disclosure is not limited to the respective aforementioned example embodiments; and a person skilled in the art can make example embodiments which include various changes through modifying and substituting the respective aforementioned example embodiments without departing from the spirit and scope of the present disclosure. 
     The aforementioned example embodiments may also be described in whole or in part as the following supplementary notes but are not limited thereto. 
     (Supplementary Note 1) 
     A stock management device comprising: 
     management means for managing stock information about stock of an item held by each of a plurality of mobile sales vehicles; 
     first reception means for receiving, from each of the plurality of mobile sales vehicles, sales information indicating an item sold at a storefront of the mobile sales vehicle and state information indicating a state of the mobile sales vehicle; 
     first transmission means for transmitting, to a customer terminal, sales state information indicating whether or not the mobile sales vehicle is selling an item at a storefront of the mobile sales vehicle and the stock information, the sales state information being generated based on the state information; 
     second reception means for receiving, from a customer terminal transmitting the stock information and the sales state information, order information including information about an item ordered based on the stock information and the sales state information; and 
     second transmission means for transmitting the order information to the mobile sales vehicle holding the ordered item included in the order information, wherein 
     the management means updates the stock information based on at least one of the sales information and the order information. 
     (Supplementary Note 2) 
     The stock management device according to Supplementary note 1, wherein 
     the first transmission means transmits, to the customer terminal, item information indicating an item recognized as an item of which a customer using the mobile sales vehicle is considering purchase. 
     (Supplementary Note 3) 
     The stock management device according to Supplementary note 2, wherein 
     the first reception means receives the item information from the mobile sales vehicle, and 
     the first transmission means transmits the item information to the customer terminal. 
     (Supplementary Note 4) 
     The stock management device according to Supplementary note 2, wherein 
     the first reception means receives, from the mobile sales vehicle, a captured image capturing a state of the storefront of the mobile sales vehicle, 
     the stock management device further comprises recognition means for recognizing, from the captured image, an item of which a customer using the mobile sales vehicle is considering purchase, and 
     the first transmission means transmits the item information to the customer terminal. 
     (Supplementary Note 5) 
     The stock management device according to any one of Supplementary notes 1 to 4, wherein 
     the state information is generated based on at least one of a signal indicating a change in movement of or an operating state of the mobile sales vehicle, a signal indicating a change in an engine of the mobile sales vehicle or an operating state of the engine, and a signal indicating whether or not the mobile sales vehicle is open for business. 
     (Supplementary Note 6) 
     A customer terminal comprising: 
     reception means for receiving, from a stock management device managing stock information about stock of an item held by each of a plurality of mobile sales vehicles, sales state information indicating whether or not the mobile sales vehicle is selling an item at a storefront of the mobile sales vehicle, the sales state information being generated based on state information indicating a state of each of the plurality of mobile sales vehicles, and the stock information; and 
     display control means for controlling a display device to display an ordering screen for receiving an order from a customer, the ordering screen being generated based on the stock information and the sales state information. 
     (Supplementary Note 7) 
     The customer terminal according to Supplementary note 6, wherein, 
     when the sales state information indicates that the mobile sales vehicle is selling an item at the storefront, the display control means gets an item included in the stock information related to the mobile sales vehicle displayed on the ordering screen in a different manner from an item included in stock information related to another mobile sales vehicle. 
     (Supplementary Note 8) 
     The customer terminal according to Supplementary note 6 or 7, wherein 
     the reception means further receives item information indicating an item of which a customer using the mobile sales vehicle is considering purchase, and 
     the display control means controls to display the ordering screen in an understandable manner for a customer that an item indicated by the item information is likely to be purchased at the storefront of the mobile sales vehicle. 
     (Supplementary Note 9) 
     The customer terminal according to any one of Supplementary notes 6 to 8, wherein 
     the state information is generated based on at least one of a signal indicating a change in movement of or an operating state of the mobile sales vehicle, a signal indicating a change in an engine of the mobile sales vehicle or an operating state of the engine, and a signal indicating whether or not the mobile sales vehicle is open for business. 
     (Supplementary Note 10) 
     An item sales system comprising: 
     a stock management device; 
     an on-board device being loaded on each of a plurality of mobile sales vehicles and transmitting, to the stock management device, sales information indicating an item sold at a storefront of each of the plurality of mobile sales vehicle and state information indicating a state of the mobile sales vehicle; and 
     one or more customer terminals, wherein 
     the stock management device includes:
         management means for managing stock information about stock of an item held by each of the plurality of mobile sales vehicles;   first reception means for receiving the sales information and the state information;   first transmission means for transmitting, to the customer terminal, sales state information indicating whether or not the mobile sales vehicle is selling an item at the storefront, the sales state information being generated based on the state information, and the stock information;   second reception means for receiving, from a customer terminal transmitting the stock information and the sales state information, order information including information about an item ordered based on the stock information and the sales state information; and   second transmission means for transmitting the order information to the on-board device on the mobile sales vehicle holding the ordered item included in the order information, wherein       

     the management means updates the stock information based on at least one of the sales information and the order information. 
     (Supplementary Note 11) 
     The item sales system according to Supplementary note 10, wherein 
     the first transmission means transmits, to the customer terminal, item information indicating an item recognized as an item of which a customer using the mobile sales vehicle is considering purchase. 
     (Supplementary Note 12) 
     A stock management method comprising: 
     managing stock information about stock of an item held by each of a plurality of mobile sales vehicles; 
     receiving, from each of the plurality of mobile sales vehicles, sales information indicating an item sold at a storefront of the mobile sales vehicle; 
     receiving, from each of the plurality of mobile sales vehicles, state information indicating a state of the mobile sales vehicle; 
     transmitting, to a customer terminal, sales state information indicating whether or not the mobile sales vehicle is selling an item at the storefront, the sales state information being generated based on the state information, and the stock information; 
     receiving, from a customer terminal transmitting the stock information and the sales state information, order information including information about an item ordered based on the stock information and the sales state information; and 
     transmitting the order information to the mobile sales vehicle holding the ordered item included in the order information, wherein 
     updating the stock information based on at least one of the sales information and the order information. 
     (Supplementary Note 13) 
     The stock management method according to Supplementary note 12, wherein 
     transmitting, to the customer terminal, item information indicating an item recognized as an item of which a customer using the mobile sales vehicle is considering purchase. 
     (Supplementary Note 14) 
     A display control method comprising: 
     receiving, from a stock management device managing stock information about stock of an item held by each of a plurality of mobile sales vehicles, sales state information indicating whether or not the mobile sales vehicle is selling an item at a storefront of the mobile sales vehicle, the sales state information being generated based on state information indicating a state of each of the plurality of mobile sales vehicles, and the stock information; and 
     controlling a display device to display an ordering screen for receiving an order from a customer, the ordering screen being generated based on the stock information and the sales state information. 
     (Supplementary Note 15) 
     The display control method according to Supplementary note 14, wherein, 
     when the sales state information indicates that the mobile sales vehicle is selling an item at the storefront, gets an item included in the stock information related to the mobile sales vehicle displayed on the ordering screen in a different manner from an item included in stock information related to another mobile sales vehicle. 
     (Supplementary Note 16) 
     A stock management method in an item sales system including a stock management device, an on-board device being loaded on each of a plurality of mobile sales vehicles, and one or more customer terminals, the stock management method comprising: 
     managing, by the stock management device, stock information about stock of an item held by each of the plurality of mobile sales vehicles; 
     transmitting, by the on-board device, to the stock management device, sales information indicating an item sold at a storefront of the mobile sales vehicle loaded with the on-board device and state information indicating a state of the mobile sales vehicle; 
     receiving, by the stock management device, the sales information; 
     receiving, by the stock management device, the state information; 
     transmitting, by the stock management device, to the customer terminal, sales state information indicating whether or not the mobile sales vehicle is selling an item at the storefront, the sales state information being generated based on the state information, and the stock information; 
     receiving, by the customer terminal, the stock information and the sales state information; 
     transmitting, by the customer terminal, to the stock management device, order information including information about an item ordered based on the stock information and the sales state information; 
     receiving, by the stock management device, the order information from the customer terminal; 
     transmitting, by the stock management device, the order information to the on-board device on the mobile sales vehicle holding the ordered item included in the order information; and 
     updating, by the stock management device, the stock information based on at least one of the sales information and the order information. 
     (Supplementary Note 17) 
     The stock management method according to Supplementary note 16, wherein 
     the stock management device transmits, to the customer terminal, item information indicating an item recognized as an item of which a customer using the mobile sales vehicle is considering purchase. 
     (Supplementary Note 18) 
     A computer-readable, non-transitory recording medium recording a program causing a computer to execute: 
     a process of managing stock information about stock of an item held by each of a plurality of mobile sales vehicles; 
     a process of receiving, from each of the plurality of mobile sales vehicles, sales information indicating an item sold at a storefront of the mobile sales vehicle; 
     a process of receiving, from each of the plurality of mobile sales vehicles, state information indicating a state of the mobile sales vehicle; 
     a process of transmitting, to a customer terminal, sales state information indicating whether or not the mobile sales vehicle is selling an item at the storefront, the sales state information being generated based on the state information, and the stock information; 
     a process of receiving, from a customer terminal transmitting the stock information and the sales state information, order information including information about an item ordered based on the stock information and the sales state information; 
     a process of transmitting the order information to the mobile sales vehicle holding the ordered item included in the order information; and 
     a process of updating the stock information based on at least one of the sales information and the order information. 
     (Supplementary Note 19) 
     The recording medium according to claim  18 , wherein storing the program causing a computer to execute: 
     a process of transmitting, to the customer terminal, item information indicating an item recognized as an item of which a customer using the mobile sales vehicle is considering purchase. 
     (Supplementary Note 20) 
     A computer-readable, non-transitory recording medium recording a program causing a computer to execute: 
     a process of receiving, from a stock management device managing stock information about stock of an item held by each of a plurality of mobile sales vehicles, sales state information indicating whether or not the mobile sales vehicle is selling an item at a storefront of the mobile sales vehicle, the sales state information being generated based on state information indicating a state of each of the plurality of mobile sales vehicles, and the stock information; and 
     a process of controlling a display device to display an ordering screen for receiving an order from a customer, the ordering screen being generated based on the stock information and the sales state information. 
     (Supplementary Note 21) 
     The recording medium according to Supplementary note 20, wherein, 
     the process of controlling the display device to display the ordering screen is a process of, when the sales state information indicates that the mobile sales vehicle is selling an item at the storefront, getting an item included in the stock information related to the mobile sales vehicle displayed on the ordering screen in a different manner from an item included in stock information related to another mobile sales vehicle. 
     This application claims priority based on Japanese Patent Application No. 2016-162551 filed on Aug. 23, 2016, the disclosure of which is hereby incorporated by reference thereto in its entirety. 
     REFERENCE SIGNS LIST 
     
         
           1  Item sales system 
           2  Item sales system 
           10  Stock management device 
           11  Management unit 
           12  First reception unit 
           13  First transmission unit 
           14  Second reception unit 
           15  Second transmission unit 
           20  On-board device 
           30  Customer terminal 
           31  Reception unit 
           32  Display control unit 
           100  Stock management device 
           101  Stock management device 
           110  Management unit 
           120  First reception unit 
           121  First reception unit 
           130  First transmission unit 
           131  First transmission unit 
           140  Second reception unit 
           150  Second transmission unit 
           160  Stock information storage unit 
           170  Customer information storage unit 
           181  Recognition unit 
           200  On-board device 
           201  On-board device 
           210  Sales information acceptance unit 
           220  Transmission unit 
           221  Transmission unit 
           230  Detection unit 
           240  Reception unit 
           251  Imaging unit 
           261  Recognition unit 
           300  Customer terminal 
           310  Reception unit 
           320  Control unit 
           330  Display unit 
           340  Acceptance unit 
           350  Transmission unit