Reader/writer and communication method thereof

A reader/writer (10, 100, 200) is provided. The reader/writer performing radio communication with a radio communication terminal (50) in close proximity thereto, includes: an antenna (11, 101, 201) which transmits a carrier wave of a predetermined frequency and which receives a composite wave of the carrier wave and a modulated signal of the carrier wave transmitted from the radio communication terminal; a demodulating unit (21, 121, 221) which demodulates the composite wave received by the antenna; a judging unit (32) which judges whether or not it is difficult to detect a modulated component included in the composite wave received by the antenna when the radio communication terminal is in close proximity; and a carrier-wave control unit which reduces a component of the carrier wave input into the demodulating unit when the judging unit judges that it is difficult to detect the modulated component.