A device registration system comprising: - an image forming apparatus, a mobile terminal, and a server, each thereof being connected or connectable to a network; - the image forming apparatus including a device near-field communication unit configured to perform near field communication with the mobile terminal; - the mobile terminal being connected or connectable to the network via an access point and including a mobile-terminal near-field communication unit configured to perform the near field communication with the image forming apparatus; wherein: the mobile terminal is configured to obtain identification information with which server can be uniquely identified in the network, from the server, and when the mobile terminal storing the identification information obtained from the server is put at a position close to the image forming apparatus, the mobile terminal establishes connection with the image forming apparatus by the near field communication, wherein the server is configured to register in a search list the image forming apparatus that is connected to the mobile terminal via the near field communication, wherein the image forming apparatus includes a memory unit having setting information of the image forming apparatus, wherein the server is configured to register the setting information in the search list, wherein, when the mobile terminal establishes connection with the image forming apparatus by the near field communication, the device near-field communication unit of the image forming apparatus is configured to transmit to the mobile terminal a first dialog screen, that includes the setting information of the image forming apparatus connected to the mobile terminal via the near field communication, a login user name area, and a password area, wherein the mobile terminal includes an operation panel for displaying the first dialog screen received from the image forming apparatus, and is configured to transmit a login user name and a password input from the login user name area and the password area to the image forming apparatus, wherein, if an authentication based on the login user name and the password is successful, the device near-field communication unit of the image forming apparatus is configured to transmit to the mobile terminal a second dialog screen, that includes the setting information of the image forming apparatus, a position information area, and a tag information area, wherein the mobile terminal is configured to display the second dialog screen received from the image forming apparatus, and to transmit position information and tag information input by the user from the position information area and the tag information area to the image forming apparatus, the position information being obtained by a global positioning system processor of the mobile terminal, and the tag information being attached to identify the image forming apparatus, wherein the image forming apparatus further includes a controller configured to update the setting information when the position information and the tag information are received, and store the updated setting information in the memory unit, and wherein, when the image forming apparatus is configured to transmit the updated setting information to the server, the server is configured to register the updated setting information in the search list. - an image forming apparatus, a mobile terminal, and a server, each thereof being connected or connectable to a network; - the image forming apparatus including a device near-field communication unit configured to perform near field communication with the mobile terminal; - the mobile terminal being connected or connectable to the network via an access point and including a mobile-terminal near-field communication unit configured to perform the near field communication with the image forming apparatus; the mobile terminal is configured to obtain identification information with which server can be uniquely identified in the network, from the server, and when the mobile terminal storing the identification information obtained from the server is put at a position close to the image forming apparatus, the mobile terminal establishes connection with the image forming apparatus by the near field communication, wherein the server is configured to register in a search list the image forming apparatus that is connected to the mobile terminal via the near field communication,