The invention provides a semiconductor device to minimize delamination of the conductive material pattern on the insulating layer. The semiconductor device (10) includes a metal substrate (11), semiconductor elements (30, 32), wires (35, 36, 37, 38), a control terminal (40), a main electrode terminal (42), a control substrate (44), a cover (45), a sealing resin (50), a case (20), and an insulator (18). The metal substrate (11) includes a metal plate (12), an insulating layer (14) formed on the top surface of the metal plate (12), and electrode patterns (16) provided on the insulating layer (14). The semiconductor elements (30, 32) are secured to the electrode patterns (16) by solder (34). The sealing resin (50) seals the components within the case (20), such as the semiconductor elements (30, 32). The insulator (18) covers a portion of the surface of the insulating layer (14) and at least a portion of the edge (16b) of each electrode pattern (16).