A plurality of output MOSFETs (1) whose drains and sources are made common and control circuits (2) containing MOSFETs (10) for cutting gates connected between the gates of the output MOSFETs (1) and the input terminals are formed on one semiconductor substrate or one mounting substrate. The number of the output MOSFETs (1) to which input signals from the input terminal are fed is increased by turning on the MOSFETs (10) by means of the control circuits (2) according to the increase of the output current.
