In one surface of a semiconductor substrate, an active region in which main current flows and an IGBT is disposed is formed. A termination structure portion serving as an electric-field reduction region is formed laterally with respect to the active region. In the termination structure portion, a porous-oxide-film region, a p-type guard ring region, and an n+-type channel stopper region are formed. A plurality of floating electrodes are formed to contact the surface of the porous-oxide-film region. Another plurality of floating electrodes are formed to contact a first insulating film.