Distortion is effectively reduced in a wide frequency band of an output signal from an amplifier. A distortion compensation apparatus includes: a distortion compensation processing section that performs a distortion compensation process on an input signal to the amplifier, based on a first amplifier model of the amplifier, and output a compensated signal; a signal generation section that receives the compensated signal and a first digital monitor signal, and generates a second digital monitor signal; and an estimation section that estimates the first amplifier model, based on the compensated signal and the second digital monitor signal. The first digital monitor signal is a signal generated by subjecting an analog monitor signal obtained by monitoring an output signal from the amplifier, to analog-to-digital conversion. A monitor band of the first digital monitor signal is narrower than a frequency band of the compensated signal. A frequency band of the second digital monitor signal is wider than the monitor band of the first digital monitor signal, and includes signal components obtained by restoring signal components outside the monitor band, among signal components included in the analog monitor signal. The signal generation section restores the signal components outside the monitor band among the signal components included in the analog monitor signal, based on the compensated signal and the first digital monitor signal.