To cancel all the unwanted distortion of radio frequency(RF) amplifier by providing a linearity and phase corrector, with which predistortion is applied to a signal to be supplied to the RF amplifier, and inserting this frequency response and phase corrector between the linearity corrector and the amplifier.

By adjusting the non-linearity and target frequency of specified amplifier 170 through a linearity corrector 164 and a phase corrector 162 which are adjusted so as to invert the amplitude and phase response of non-linear amplifier, the phase corrector 162 prevents the precorrecting adjustment of amplitude from exerting any adverse influence upon the precorrection of phase while being provided on the upper step of linearity corrector 164. Then, a frequency response corrector 166 is provided between the linearity corrector 164 and amplitude input circuit 168 so as to compensate an input signal. Since an amplifier output circuit 172 changes the frequency and phase response of entire system sometimes, by providing a frequency response corrector 160, the frequency response and phase response of entire system are corrected transparent.