To provide a communication system which adopts an orthogonal multi-carrier system that obtains delay information of a received wave.

A known signal demodulation circuit 108 applies OFDM demodulation processing to the output of an equalizer 105 to output a demodulation signal Sr, and a divider 109 applies complex division to a data part of a known signal So of a database 111. A fluctuation calculation result Sa is obtained by each subcarrier (1,..., n) from the data part 10b of the known signal 10. A delay analysis arithmetic circuit 110 uses the fluctuation calculation result Sa by each subcarrier (1,..., n) to analyze a delay wave (step 302). As a delay wave analysis method, ESPIT method is adopted, and delay wave information 112 is obtained by using the fluctuation calculation result Sa by each subcarrier (1,..., n).