A distortion compensation device includes a generating unit, a calculation unit, a conversion unit, and a distortion compensation unit. The generating unit generates, from an output signal of a power amplifying unit that amplifies transmission signals having a plurality of different bands, a superimposed signal in which the transmission signals having the different bands have been superimposed. The calculation unit calculates, based on the superimposed signal, a coefficient indicating a forward characteristic of nonlinear distortion of the power amplifying unit associated with each of the transmission signals having the different bands. The conversion unit converts the coefficient calculated by the first calculation unit to a coefficient indicating an inverse characteristic of the nonlinear distortion of the power amplifying unit. The distortion compensation unit performs, by using the coefficients converted by the first conversion unit, a predistortion process on each of the transmission signals having different bands.