A semiconductor device includes: first and second metallic plates, each of which includes a heat radiation surface and an inner surface; a semiconductor element between the metallic plates; a block between the second metallic plate and the semiconductor element; a solder member between the second metallic plate and the block; and a resin mold. The heat radiation surface is exposed from the resin mold. The second metallic plate includes a groove for preventing the solder member from expanding outside of the block. The groove is disposed on the inner surface and disposed on an outer periphery of the block. The second metallic plate further includes an inner surface member on an inner surface of the groove. The inner surface member has a solder wettability, which is larger than a solder wettability of the block.