It is an object to provide a power semiconductor module having a case shared for base plates of different sizes and having a high-stability base plate. The power semiconductor module according to the present invention includes: a base plate; an insulating substrate disposed on a first main surface of the base plate; a semiconductor chip disposed on an insulating substrate; a case for enclosing the base plate except a second main surface of the base plate facing the first main surface, the insulating substrate, and the semiconductor chip; and a spacer provided between the outer periphery of the base plate and the inner periphery of the case and in contact with both. The spacer has a bonding surface with a side surface of the base plate and the first main surface in the contact with the outer periphery of the base plate.