The present invention is applied to a switching amplifier that includes a first high-side gate and a first low-side gate having output terminals connected together, and a high-side driver and a low-side driver that drive the first high-side gate and the first low-side gate, respectively. In the switching amplifier of the present invention, the high-side driver includes an input switching amplifier that uses the output terminal of the first high-side gate as a power source.