Included are an insulating plate 41 including a plurality of insulating synthetic resin layers, wiring circuits 44a, 44b, and 44c provided in the insulating plate 41, a thin-film resistor 46 formed to be buried in the insulating plate 41 and electrically connected to the wiring circuits 44a, 44b, and 44c, a heat dissipating portion 47 provided over one surface of the insulating plate to be opposed to the thin-film resistor 46 via a part of the plurality of insulating synthetic resin layers and having higher heat conductivity than that of the insulating plate 41, a pedestal portion 48 formed to be buried in the insulating plate 41 and provided to be opposed to the thin-film resistor 46 via a part of the plurality of insulating synthetic resin layers on an opposite side of the heat dissipating portion 47 and having higher heat conductivity than that of the insulating plate 41, and a heat dissipation and pedestal connecting portion 49 connecting the heat dissipating portion 47 to the pedestal portion 48 and having higher heat conductivity than that of the insulating plate 41.