A non-linear distortion signal contained in output signal components from a high-frequency power amplifier is detected, while a non-linear distortion signal is generated from a high-frequency signal to be amplified. Correlation between this non-linear distortion signal and the detected non-linear distortion signal is determined, and a control variable is calculated based on the signal thus obtained. The obtained control variable is multiplied by the generated non-linear distortion signal to generate a distortion compensation signal, which is added to the signal to be amplified. This provides a distortion compensation device capable of automatically maintaining optimum distortion compensation characteristics and rapidly achieving desirable distortion compensation.