A semiconductor device includes: a semiconductor element; a metallic plate having a heat radiation surface; a terminal connecting to the element; and a resin mold covering the element, the plate and the terminal. The metallic plate provides an electrode of the semiconductor element. The heat radiation surface is capable of radiating heat generated in the element. The heat radiation surface and a part of the terminal are exposed from the resin mold. The resin mold includes a concavity/convexity portion between the heat radiation surface and the part of the terminal in order to lengthen a creepage distance therebetween. The concavity/convexity portion is disposed on a surface of the resin mold.