An object is to provide a technique capable of regulating a direction in which an adhesive agent used for bonding a base plate and a case is wetly widened. A semiconductor device includes a base plate and a case. The case is bonded to a peripheral edge part of the base plate via an adhesive agent. A dip which is an application position where the adhesive agent is applied and an inclined surface directed downward from the dip toward an outer peripheral side or an inclined surface directed downward from the dip toward an inner peripheral side are formed in the peripheral edge part of the base plate.