A distortion compensator for reducing a level of a distortion component included in an output analog signal of an amplifier, includes: an A/D converter to convert the output analog signal of the amplifier into a digital output signal; a comparator to generate a distortion characteristic of the amplifier based on a digital input signal and the digital output signal; a rate controller to control a sampling rate of the A/D converter based on the digital input signal and the digital output signal; a predistorter to multiply the digital input signal and a compensation value for compensating the amplifier, the compensation value being calculated based on the digital input signal and the distortion characteristic of the amplifier; and a D/A converter to convert multiplication result of the predistorter into an analog input signal to input the analog input signal to the amplifier.