To correctly decode divided signals using a filter bank by compensating for distortions of respective signals with band divisions.

This adaptive equalizer 100 uses a band division filter 101 to divides an input signal into M-sets of frequency bands, and a sampling rate converter 102 applies down-sampling to the signal at a sampling rate of a multiple of 1/M. Then a training processing section 105 receives a known training signal and applies a training processing to the signal to correct distortions, a sampling rate converter 103 applies up-sampling to the resulting signal and a synthesis filter 104 decodes the signal into the original signal.