Disclosed is a distortion compensation apparatus that, by appropriately generating a distortion-compensation coefficient, makes it possible to obtain a desired transmission output, and substantially reduce the amount of power leakage to an adjacent channel. Reception section (103) of the distortion compensation apparatus acquires and demodulates a transmission signal to generate a demodulation signal. Delay adjustment section (104) computes the delay amount of the demodulation signal with respect to the baseband signal, eliminates the delay of the demodulation signal with respect to the baseband signal based on the delay amount, and outputs the baseband signal and the demodulation signal in which the delay is eliminated. Distortion compensation section (101) determines a distortion compensation coefficient in an adaptive digital predistortion process based on the baseband signal and the demodulation signal output by delay adjustment section (104), and multiplies the input signal by the distortion compensation coefficient.