A cooling device comprising: a frame-shaped frame body; a supply port configured to supply a cooling medium into the frame body; a discharge port configured to discharge the cooling medium in the frame body to an exterior of the frame body; a projection portion (38, 40, 108) integrally formed with the frame body that projects from an inner side face of the frame body and forms a fluid channel along which the cooling medium flows in the frame body from the supply port to the discharge port; two cover bodies (26, 28) that cover openings at both thickness direction sides of the frame body, respective inner faces of the cover bodies (26, 28) being welded or brazed to the frame body and the projection portion (38, 40, 108); and fixing-receiving portions that are provided in the projection portion (38, 40) spaced apart in the direction of projection, fixing members that penetrate through each of the two cover bodies (26, 28) and are configured to fix a cooled member to an outer face of one of the cover bodies (26, 28), the fixing members being retained at the fixing-receiving portions, wherein the supply port is provided at the frame body, and the discharge port is provided at the frame body, wherein holding portions (48A, 48B) are provided at the projection portion (38, 40), the holding portions (48A, 48B) being protrusions that protrude perpendicular to the projection portion (38, 40, 108) from side walls of the projection portion (38, 40, 108), a fin member disposed in the fluid channel and being held at the holding portions (48A, 48B) and the holding portions (48A, 48B) positioning the fin member with respect to the frame body, and the holding portions (48A, 48B) are provided at a distal end side and a proximal end side of the projection portion (38, 40), the fin member being sandwiched by the holding portions (48A, 48B). a frame-shaped frame body; a supply port configured to supply a cooling medium into the frame body; a discharge port configured to discharge the cooling medium in the frame body to an exterior of the frame body; a projection portion (38, 40, 108) integrally formed with the frame body that projects from an inner side face of the frame body and forms a fluid channel along which the cooling medium flows in the frame body from the supply port to the discharge port; two cover bodies (26, 28) that cover openings at both thickness direction sides of the frame body, respective inner faces of the cover bodies (26, 28) being welded or brazed to the frame body and the projection portion (38, 40, 108); and fixing-receiving portions that are provided in the projection portion (38, 40) spaced apart in the direction of projection, fixing members that penetrate through each of the two cover bodies (26, 28) and are configured to fix a cooled member to an outer face of one of the cover bodies (26, 28), the fixing members being retained at the fixing-receiving portions, wherein the supply port is provided at the frame body, and the discharge port is provided at the frame body, wherein holding portions (48A, 48B) are provided at the projection portion (38, 40), the holding portions (48A, 48B) being protrusions that protrude perpendicular to the projection portion (38, 40, 108) from side walls of the projection portion (38, 40, 108), a fin member disposed in the fluid channel and being held at the holding portions (48A, 48B) and the holding portions (48A, 48B) positioning the fin member with respect to the frame body, and the holding portions (48A, 48B) are provided at a distal end side and a proximal end side of the projection portion (38, 40), the fin member being sandwiched by the holding portions (48A, 48B).