A semiconductor module comprising: a case including a receiving space which is formed by a frame portion (304A3) and a pair of wall portions (304A1, 304A2) disposed to face each other with the frame portion (304A3) therebetween, the pair of wall portions (304A1, 304A2) including a heat dissipation portion (307A, 307B, 307C) and a support wall which supports the heat dissipation portion (307A, 307B, 307C) at the frame portion (304A3); a plurality of semiconductor device blocks (3000A, 3000B) which are disposed in parallel in the receiving space while facing the wall portion (304A1, 304A2), wherein a conductor plate (315, 316, 318, 319) is joined to each of electrode surfaces formed at both sides of a semiconductor device (155, 156, 157, 158); a plurality of insulating sheet members which are respectively interposed between the respective conductor plates (315, 316, 318, 319) and an inner periphery of the wall portion (304A1, 304A2) to insulate the respective conductor plates (315, 316, 318, 319) and the inner periphery of the wall portion (304A1, 304A2); and a resin composition member which is filled in the receiving space to seal the plurality of semiconductor device blocks (3000A, 3000B), characterized in that the heat dissipation portion (307A, 307B) provided at least one side of the wall portion (304A1) includes a plurality of separate heat dissipation portions (307A, 307B) disposed to face the plurality of semiconductor device blocks (3000A, 3000B) respectively, and the plurality of separate heat dissipation portions (307A, 307B) is surrounded by the support wall, wherein the support wall is thinner than the plurality of separate heat dissipation portions (307A, 307B) and is deformable to a recessed state by pressing the heat dissipation portions (307A, 307B) to a case-inside direction, and the support wall, when deformed to the recessed state, is inclined toward the inside of the case from the frame portion (304A3) to the separate heat dissipation portion (307A, 307B) such that the insulating sheet members are closely joined to the respective conductor plate (318, 319) and the respective separate heat dissipation portion (307A, 307B). a case including a receiving space which is formed by a frame portion (304A3) and a pair of wall portions (304A1, 304A2) disposed to face each other with the frame portion (304A3) therebetween, the pair of wall portions (304A1, 304A2) including a heat dissipation portion (307A, 307B, 307C) and a support wall which supports the heat dissipation portion (307A, 307B, 307C) at the frame portion (304A3); a plurality of semiconductor device blocks (3000A, 3000B) which are disposed in parallel in the receiving space while facing the wall portion (304A1, 304A2), wherein a conductor plate (315, 316, 318, 319) is joined to each of electrode surfaces formed at both sides of a semiconductor device (155, 156, 157, 158); a plurality of insulating sheet members which are respectively interposed between the respective conductor plates (315, 316, 318, 319) and an inner periphery of the wall portion (304A1, 304A2) to insulate the respective conductor plates (315, 316, 318, 319) and the inner periphery of the wall portion (304A1, 304A2); and a resin composition member which is filled in the receiving space to seal the plurality of semiconductor device blocks (3000A, 3000B), characterized in that the heat dissipation portion (307A, 307B) provided at least one side of the wall portion (304A1) includes a plurality of separate heat dissipation portions (307A, 307B) disposed to face the plurality of semiconductor device blocks (3000A, 3000B) respectively, and the plurality of separate heat dissipation portions (307A, 307B) is surrounded by the support wall, wherein the support wall is thinner than the plurality of separate heat dissipation portions (307A, 307B) and is deformable to a recessed state by pressing the heat dissipation portions (307A, 307B) to a case-inside direction, and the support wall, when deformed to the recessed state, is inclined toward the inside of the case from the frame portion (304A3) to the separate heat dissipation portion (307A, 307B) such that the insulating sheet members are closely joined to the respective conductor plate (318, 319) and the respective separate heat dissipation portion (307A, 307B).