A semiconductor device includes a plurality of die pad sections, a plurality of semiconductor chips, each of which is arranged in each of the die pad sections, a resin encapsulation portion having a recess portion for exposing at least a portion of the die pad sections, the resin encapsulation portion configured to cover the die pad sections and the semiconductor chips, and a heat radiation layer arranged in the recess portion. The heat radiation layer includes an elastic layer exposed toward a direction in which the recess portion is opened. The heat radiation layer directly faces at least a portion of the die pad sections. The elastic layer overlaps with at least a portion of the die pad sections when seen in a thickness direction of the heat radiation layer.