A semiconductor light emitting device that is excellent in radiating heat and that can be molded into a sealing shape having intended optical characteristics by die molding is provided. The semiconductor light emitting device includes: a lead frame including a plate-like semiconductor light emitting element mounting portion having an LED chip mounted on a main surface, and a plate-like metal wire connecting portion extending over a same plane as the semiconductor light emitting element mounting portion; a metal wire electrically connecting the LED chip and the metal wire connecting portion; a thermosetting resin molded by die molding or dam-sheet molding so as to completely cover the LED chip and the metal wire; and a resin portion provided to surround the lead frame and having the thickness not greater than the thickness of the lead frame.