A trench gate IGBT designed to reduce on-state voltage while maintaining the withstand voltage, including a first drift layer formed on a first main surface of a buffer layer, a second drift layer of the first conductivity type formed on said first drift layer, a base layer of a second conductivity type formed on the second drift layer, an emitter layer of the first conductivity type selectively formed in the surface of the base layer, and a gate electrode buried from the surface of the emitter layer through into the second drift layer with a gate insulating film therebetween, wherein said first drift layer has a structure in which a first layer of the first conductivity type and a second layer of the second conductivity type are repeated in a horizontal direction.