A distortion compensator 10 acquires an asymmetric component included in a 1-bit pulse train outputted from a DSM 6 on the basis of an analog signal as an output signal obtained from the 1-bit pulse train, and an IQ signal as an input signal to be inputted to the DSM 6, and performs distortion compensation on the basis of the asymmetric component. The distortion compensator 10 is caused to store therein asymmetric component data representing the acquired asymmetric component. When acquiring the asymmetric component, the distortion compensator 10 acquires, as an asymmetric component, a difference between an output baseband signal obtained by orthogonally demodulating the analog signal as the output signal, and an input baseband signal before being orthogonally modulated.