To provide a nonlinear distortion equalizing circuit capable of compensating nonlinear distortion with a small circuit scale even when the nonlinear distortion equalizing circuit is adopted for a code multiplexing system such as the OFCDM system.

A nonlinear distortion compensation complex signal conversion circuit 102 distributes a baseband input signal S101 into two, applies complex cube operations to one signal and adds the processed one signal to the other signal to compensate nonlinear distortion, and a line compensation circuit 109 eliminates linear distortion. An FFT 122 applies FFT processing to the other signal subjected to complex cube processing by a complex cube circuit 103, thereafter a replica processing section 121 and a coefficient update section 140 carry out timing adjustment and repetitive up-sampling by a multiple of a spread coefficient for a ternary distortion replica demodulation signal calculated by a first inverse spread circuit 113 through inverse spread processing and an error signal calculated by an error calculation circuit 114 so as to update a coefficient when the nonlinear distortion compensation complex signal conversion circuit 102 carries out complex cube processing. Thus, the circuit scale of the replica processing section 121 can be reduced because the nonlinear distortion is compensated by a signal by one code.