An apparatus includes: a unit that stores the look-up table including distortion compensation coefficients; a unit that selects addresses according to an input signal, acquires coefficients stored at the selected addresses, and performs the predistortion of the input signal by using the acquired coefficients; a unit that calculates an error signal by comparing with the input signal a feedback signal that indicates an output of a power amplifier to which a result of the predistortion is inputted; a unit that calculates coefficients from the error signal and the acquired coefficients by using the adaptive algorithm; a unit that, for each of the selected addresses, selects coefficients as adequate coefficients from among the calculated coefficients according to the error signal; and a unit that, for each of the selected addresses, calculates an average value of the adequate coefficients and replaces a stored coefficient in the look-up table with the average value.