To realize synchronous demodulation in an IS-200 (Interim Standard 2000) system so as to improve the reception performance and increase the number of subscribers.

The synchronous demodulating apparatus includes: a first synchronous demodulation unit for receiving reception signals r(t) from a plurality (K) of terminals and generating and outputting demodulated user signals d'1 to d'K; a channel estimate unit for receiving the reception signals r(t) to estimate and output channel parameters A1(t-Tb) to AK(t-Tb); an interference signal reproducing unit for receiving the plurality (K) of user demodulation signals d'1 to d'K from the first synchronous demodulation unit, generating respective interference signals corresponding to a plurality (K) of subscribers, eliminating the interference signals by using the received signals r(t-Tb) delayed by about 1 symbol and outputting a plurality of interference-eliminated signals r'1(t-Tb) to r'K(r-Tb); and a second synchronous demodulation unit for demodulating and outputting the plurality of interference-eliminated signals r'1(t-Tb) to r'K(r-Tb) received from the interference signal reproducing unit.