A gain control circuit includes a comparator that compares an input gain value with a count value to generate a comparison result signal, a counter that counts up or counts down the count value in accordance with the comparison result signal, and a gain modulator circuit that modulates the count value to generate a gain control signal which changes in a time-divided manner. The gain modulator circuit modulates the count value so that a gain obtained by time-averaging a gain corresponding to the gain control signal matches a gain based on the count value.