A semiconductor device includes a heater element; a first heat sink disposed on one side of the heater element; a second heat sink disposed on the other side of the heater element; and a resin mold for molding the heater element and the first and second heat sinks. The first heat sink includes a first heat radiation surface, which is disposed opposite to the heater element and exposed from the resin mold. The second heat sink includes a second heat radiation surface, which is disposed opposite to the heater element and exposed from the resin mold. The first and second heat radiation surfaces have a degree of parallelism therebetween equal to or smaller than 0.2 mm.