PURPOSE: To perfrm accelerated operation in an insulated gate type semiconductor device by employing as the second transistor forming the semiconductor device a transistor exhibiting preferable normally ON current non-saturable characteristic, thereby eabling to flow large current.

CONSTITUTION: An n+ type source region 2, an n type active layer 12, an n+ type drain region 13, an n type active layer 14 and a p+ type anode region 15 are continuously formed on an insulated substrate 1, and the first transistor is formed with the region 2, the layers 12 and the region 13 while commonly using the central region 13. The second transistor is formed of the region 13, the layer 14 and the region 15 in such a manner that the thickness tc of the layer 14 is suppressed to three times the device length of the intrinsic semiconductor forming the layer 14. Thereafter, an anode electrode 16 and a source electrode 7 are formed on the region 15 and 2, and the first gate electrode 9 is formed through a gate insulating film 8 on the layer 12, and the second gate common electrode 17 is formed on the layer 14 through other gate insulating film 8 from the region 13. In this manner, the prescribed characteristics can be provided at the second transistor, thereby accelerating the operation of the device.