To provide a lateral bipolar transistor which exhibits a high early voltage by inhibiting base width modulation effect without increasing the size of the device.

In a lateral bipolar transistor, a P-type emitter region 6 is formed in a major surface of an N-type base region 3. A P-type collector region 7 is arranged on the outer region separated from the emitter region 6. An emitter electrode 9 is extended to above the collector region 7 via an insulating film 5. The insulating film 5 under the emitter electrode 9 is made thick near the collector region 7 and thin near the emitter region 6. A region where electrons are accumulated is formed in the base region 3 under the thin insulating film by the potential difference applied between the emitter and the base. A depletion layer extending from the collector region 7 is formed under the thick insulating film by the potential difference applied between the collector and the base.