A communication system comprising a communication apparatus, an external device like for example a refrigerator, a washing machine, and a microwave oven, and further comprising a server, wherein the communication apparatus is adapted to communicate with the server connected via a network and also communicate with the external device provided with a RFID tag by using near-field communication, and wherein the external device has a guide pattern formed on one surface representing a position of an antenna performing near-field communication as the RFID tag, and wherein the communication apparatus comprises: a loop antenna adapted to output a polling signal by near-field communication to the RFID tag provided in the external device, and to receive a polling response by near-field communication from the RFID tag provided in the external device that has received the polling signal; a display unit provided on a side of the communication apparatus opposite an orientation in which the loop antenna is adapted to transmit the polling signal and to receive the polling response; a communication apparatus identification information storing unit adapted to store communication apparatus identification information for identifying the communication apparatus; a position information acquisition unit adapted to transmit the communication apparatus identification information stored in the communication apparatus identification information storing unit to the server and to acquire, from the server, antenna position information that represents a position of the loop antenna in the communication apparatus and that corresponds to the communication apparatus identification information; a position information storing unit adapted to store the acquired antenna position information; a selection acceptance unit adapted to accept selection of the external device; and a guide pattern acquisition unit adapted to transmit external device identification information for identifying the external device selected by the selection acceptance unit to the server, and to acquire a guide pattern corresponding to the external device identification information, wherein the display unit is adapted to display the guide pattern acquired by the guide pattern acquisition unit at the position of the loop antenna on the basis of the antenna position information which is stored in the position information storing unit, within a period in which the loop antenna outputs the polling signal to the external device. a loop antenna adapted to output a polling signal by near-field communication to the RFID tag provided in the external device, and to receive a polling response by near-field communication from the RFID tag provided in the external device that has received the polling signal; a display unit provided on a side of the communication apparatus opposite an orientation in which the loop antenna is adapted to transmit the polling signal and to receive the polling response; a communication apparatus identification information storing unit adapted to store communication apparatus identification information for identifying the communication apparatus; a position information acquisition unit adapted to transmit the communication apparatus identification information stored in the communication apparatus identification information storing unit to the server and to acquire, from the server, antenna position information that represents a position of the loop antenna in the communication apparatus and that corresponds to the communication apparatus identification information; a position information storing unit adapted to store the acquired antenna position information; a selection acceptance unit adapted to accept selection of the external device; and a guide pattern acquisition unit adapted to transmit external device identification information for identifying the external device selected by the selection acceptance unit to the server, and to acquire a guide pattern corresponding to the external device identification information, wherein the display unit is adapted to display the guide pattern acquired by the guide pattern acquisition unit at the position of the loop antenna on the basis of the antenna position information which is stored in the position information storing unit, within a period in which the loop antenna outputs the polling signal to the external device.