Provided is a load fluctuation compensation circuit for compensating a power source voltage supplied to an operation circuit, the load fluctuation compensation circuit including: a periodic signal changing section that receives a power source voltage from a power source shared with the operation circuit, and outputs a changed signal resulting from changing a supplied periodic signal according to the power source voltage; a phase comparator that compares a phase of the periodic signal with a phase of the changed signal outputted from the periodic signal changing section; an initializing section that generates a bias voltage supplied to the periodic signal changing section and adjusts a phase difference between the periodic signal and the changed signal to a preset value, based on the comparison result of the phase comparator; a controller that holds the bias voltage outputted from the initializing section when the phase difference between the periodic signal and the changed signal has become the preset value; a power current consumption circuit that shares a power source with the operation circuit; and a fluctuation compensation section that controls an amount of a power current supplied to the power current consumption circuit, based on the comparison result outputted from the phase comparator while the bias voltage of the initializing section is kept on hold.