An RB-IGBT is provided that has a new emitter trench structure with improved breakdown voltage achieved by improving the electrical field distribution of the drift region. The RB-IGBT includes an isolation region having a first conductivity type on a side surface of a semiconductor substrate. The semiconductor substrate includes a drift region having a second conductivity type; a collector region having the first conductivity type and provided farther downward than the drift region; and an emitter trench portion provided extending to the drift region in a thickness direction from a front surface to a back surface of the semiconductor substrate. The emitter trench portion includes a trench electrode electrically connected to an emitter electrode provided above the semiconductor substrate; an upper trench insulating film directly contacting a bottom portion and side portions of the trench electrode; and a lower trench insulating film provided below the upper trench insulating film.