A semiconductor module comprising: a lead frame which is formed of a plurality of terminals and on which electronic components are mounted; an insulating sheet arranged in parallel with the lead frame on the rear surface side of the lead frame with respect to the surface where the electronic components are mounted; and a resin sealing body which seals the lead frame, the electronic components and the insulating sheet, wherein a peripheral portion of the insulating sheet on the rear surface side with respect to the surface in contact with the lead frame is covered by the resin sealing body, and a central portion of the insulating sheet corresponding to the portion inside of the peripheral portion is exposed as a region that is not sealed by the resin sealing body, wherein the lead frame has terminals with portions which are extended to the outside of the resin sealing body, hereinafter called first terminals, and the sealing by the resin sealing body is such that the first terminals also have portions that are sunken to the inside of the resin sealing body by a width which is larger than the width of the resin sealing body sealing the peripheral portion of the insulating sheet below the peripheral portion of the insulating sheet underneath the terminal portions that are sunken to the inside of the resin sealing body, and the peripheral portion of the resin sealing body below the peripheral portion of the insulating sheet has a greater overlap with the insulating sheet in a position directly below the location of the portions of the first terminals that are sunken to the inside of the resin sealing body than in a position directly below the location of a terminal not extending to the outside of the resin sealing body, the terminal not extending to the outside of the resin sealing body being located at a peripheral portion of the insulating sheet on a different side of the semiconductor module than the first terminals. a lead frame which is formed of a plurality of terminals and on which electronic components are mounted; an insulating sheet arranged in parallel with the lead frame on the rear surface side of the lead frame with respect to the surface where the electronic components are mounted; and a resin sealing body which seals the lead frame, the electronic components and the insulating sheet, wherein a peripheral portion of the insulating sheet on the rear surface side with respect to the surface in contact with the lead frame is covered by the resin sealing body, and a central portion of the insulating sheet corresponding to the portion inside of the peripheral portion is exposed as a region that is not sealed by the resin sealing body, wherein the lead frame has terminals with portions which are extended to the outside of the resin sealing body, hereinafter called first terminals, and the sealing by the resin sealing body is such that the first terminals also have portions that are sunken to the inside of the resin sealing body by a width which is larger than the width of the resin sealing body sealing the peripheral portion of the insulating sheet below the peripheral portion of the insulating sheet underneath the terminal portions that are sunken to the inside of the resin sealing body, and the peripheral portion of the resin sealing body below the peripheral portion of the insulating sheet has a greater overlap with the insulating sheet in a position directly below the location of the portions of the first terminals that are sunken to the inside of the resin sealing body than in a position directly below the location of a terminal not extending to the outside of the resin sealing body, the terminal not extending to the outside of the resin sealing body being located at a peripheral portion of the insulating sheet on a different side of the semiconductor module than the first terminals.