To improve heat dissipation of a semiconductor device using a semiconductor chip.

The semiconductor device having the semiconductor chip (30) mounted on a mounting substrate (20) of a hybrid integrated circuit is characterized by having a heat dissipation material (40) between the mounting substrate (20) below the heat dissipation material (40) and the semiconductor chip, wherein through holes (50) having internal walls covered with metal films (70) are formed in the mounting substrate (20), and heat generated by the semiconductor chip (30) is passed through the heat dissipation material (40) and the metal films (70) on the internal walls of the through holes (50), and radiated to the reverse side of the mounting substrate (20). A heat conductive material (60) is buried in each through hole (50) to efficiently release the heat of the semiconductor chip (30).