A class-D amplifier has a switching amplifying-unit, which includes a pair of switching elements. The unit drives the switching elements and generates pulse amplified switching signals. The amplifier also has a signal-generating unit, which generates pulse width modulation signals each for driving the switching elements and supplies the generated pulse-width modulation signals to the. switching amplifying-unit. The switching amplifying-unit includes a detecting sub-unit, which detects an operating state of the switching elements. The signal-generating unit includes a dead-time-setting sub-unit, which sets dead time relative to the switching elements by delaying each of the pulse width modulation signals using propagation delay times in logic devices. The signal-generating unit also includes a control sub-unit, which controls the dead-time-setting sub-unit based on a detected result of the detecting sub-unit to change the dead time based on the operating state of the switching elements.