PURPOSE: To build a current detection function in an IGBT element.

CONSTITUTION: In a cell region 100 of an IGBT, electron is injected to an n- layer 3 through an n+ source layer 5 and a channel from a source electrode 10 when a unit cell is on. Accordingly, a p-n junction 12 becomes forward bias and hole is injected to the n- layer 3 from a p+ layer 2. In the process, electron also flows in below a p layer 6 of a detection part 101 and injection of hole is also generated in the detection part 101. The excessive hole is made to flow to a source electrode 10 through a p layer 6. At this time, electric potential in accordance with the product of a transverse resistance of the p layer 6 and a hole current 23 appears to a source electric potential in a detection electrode 11 which is set through a contact hole 15 to the p layer 6. An element current can be converted by detecting the electric potential.