Each lead frame for a power chip has one side main surface on which a power chip is mounted and a suspension lead part provided projectingly from a region reserved for forming mold resin in addition to a lead terminal. Thus, the lead frame can be supported by the plurality of suspension lead parts in a molding step. A metal block is provided on the other main surface of the lead frame to face the power chip. Consequently, a semiconductor device with good heat radiation properties and good insulation breakdown voltages can be obtained.