PURPOSE: To prevent a latching effect without a diffusion potential between a source layer and a channel layer being exceeded by the potential change under a source layer, by collecting carrier to be injected from a drain region by one conductivity type layer in the drain region under the channel layer.

CONSTITUTION: The same conductivity type P+ type collector layer 32 as that of a channel forming layer is formed with substantially the same width in the N- type layer 2 of a drain region under the P-type layer 3 of a channel layer, and connected by a P+ type layer 31 to the layer 3 and a source electrode. Part of carrier (hole) 11 injected from a P+ type layer 1 to a drain region 2 is collected to the layer 32 of a collector layer, and the number of holes arriving at the layer 3 of an N+ type layer 4 is reduced. An important point to design an IGBT is of an interval W of the region 2 between the layers 32 for collecting the carrier. If the interval is excessively narrow, resistance is increased against the carrier (electrons) injected from a source layer 4 designated by a solid line 12, thereby causing a voltage drop between a source electrode 7 and a drain electrode 8 to increase.