A semiconductor laser device 1 comprises: a heat sink 20, in turn comprising a main cooler unit 21, formed by joining metal members, a fluid channel 30, formed inside the main cooler unit 21, a cooling region 23 on an outer wall surface 22, and a resin layer 40, being continuously coated onto the outer wall surface 22 and an inner wall surface 33 with the exception of the cooling region 23; and a semiconductor laser element 80, positioned at the cooling region 23 with thermal contact with the outer wall surface 22 being maintained. By continuously coating the outer wall surface 22 and the inner wall surface 33 with the resin layer 40 with the exception of the cooling region 23, prevention of corrosion near portions at which the outer wall surface and the inner wall surface contact each other is realized.