Noise caused by switching is reduced using a simple configuration in a circuit amplifying a pulse signal using a switching amplifier. A control data output section outputs control data that instructs that a pulse width of each of a pair of pulse signals be modulated. A data replacement section replaces the control data with data for replacement different from the control data in the case where the control data is output that instructs that the modulation leading to approximately a same pulse width for the pair of pulse signals be performed. A pulse width modulation circuit performs the modulation on each of the pair of pulse signals in accordance with the data for replacement. A pair of switching amplifiers amplify the pair of pulse signals that have been subjected to the modulation.