A first terminal device comprising: an output unit configured to output a terminal identification image including first terminal identification information to be captured by one or more second terminal devices to identify the first terminal device; a control unit configured to: request, from an information processing system, a list of second terminal identification information associated with the first terminal identification information and used to identify the second terminal devices, thereby acquiring, from a registration unit of an external information processing system, a list of second terminal devices that have captured the terminal identification image and acquired the included first terminal identification information, and execute processing of transmitting, to the information processing system, a content transmission request to allow the first terminal device to transmit data to a second terminal device selected from the list of second terminal devices that have acquired the first terminal identification information; and a display unit configured to display the list of second terminal devices that have acquired the first terminal identification information, whereby a control unit of the second terminal device is configured to transmit, to the information processing system, a registration request to register the first terminal identification information used to identify the first terminal device and the second terminal identification information, used to identify the second terminal device itself, in association with each other. an output unit configured to output a terminal identification image including first terminal identification information to be captured by one or more second terminal devices to identify the first terminal device; a control unit configured to: request, from an information processing system, a list of second terminal identification information associated with the first terminal identification information and used to identify the second terminal devices, thereby acquiring, from a registration unit of an external information processing system, a list of second terminal devices that have captured the terminal identification image and acquired the included first terminal identification information, and execute processing of transmitting, to the information processing system, a content transmission request to allow the first terminal device to transmit data to a second terminal device selected from the list of second terminal devices that have acquired the first terminal identification information; and request, from an information processing system, a list of second terminal identification information associated with the first terminal identification information and used to identify the second terminal devices, thereby acquiring, from a registration unit of an external information processing system, a list of second terminal devices that have captured the terminal identification image and acquired the included first terminal identification information, and execute processing of transmitting, to the information processing system, a content transmission request to allow the first terminal device to transmit data to a second terminal device selected from the list of second terminal devices that have acquired the first terminal identification information; and a display unit configured to display the list of second terminal devices that have acquired the first terminal identification information, whereby a control unit of the second terminal device is configured to transmit, to the information processing system, a registration request to register the first terminal identification information used to identify the first terminal device and the second terminal identification information, used to identify the second terminal device itself, in association with each other.