To reduce the power consumption of a reader/writer which accesses data to an IC card.

A reader/writer has an antenna, a card detection circuit which detects that an IC card is placed in an antenna connection area and a CPU. After power is inputted, the CPU detects that the card is placed in the antenna connection area from a detection signal outputted by the card detection circuit in step ST14 and activates a carrier control signal S31 to 'H' in step ST15. Thus, carrier is radiated to the card and communication with the reader/writer becomes available. When it is detected that the card is removed from the antenna connection area based on the monitoring of the detection signal in step ST16, the CPU sets the signal S31 to 'L'. That is, carrier radiation is limited only to the time when the card exists in the antenna connection area.