The cell size is reduced and device reliability is improved for a semiconductor device including plural transistors making up a multi-channel output circuit. In a multi-channel circuit configuration, a group of transistors having a common function of plural channels are surrounded by a common trench for insulated isolation from another group of transistors having another function. The collectors of mutually adjacent transistors on the high side are commonly connected to a VH power supply, whereas the emitters of mutually adjacent transistors on the low side are commonly connected to a GND power supply.