A liquid-cooled-type cooling device includes a casing which has a cooling-liquid inlet formed at a rear end portion of the casing and a cooling-liquid outlet formed at a front end portion of the casing. A corrugated fin for forming a plurality of flow channels through which a cooling liquid flows from the rear side toward the front side is disposed within the casing to be located between the cooling-liquid inlet and the cooling-liquid outlet. A heat-generating-body mounting region is provided on an outer surface of a top wall of the casing. Projections which come into contact with front and rear end portions of the corrugated fin to thereby position the corrugated fin in the front-rear direction are provided on an inner surface of the bottom wall of the casing at positions shifted, in the left-right direction, from an inner surface region corresponding to the heat-generating-body mounting region.