A semiconductor device prevents the OFF current of a complementary field effect transistor from varying with changes in ambient temperature. The semiconductor device includes: a substrate voltage generating circuit that generates the substrate voltage of an n-channel MOS transistor forming a CMOS; a replica transistor that is a replica of the n-channel MOS transistor, and is diode-connected; and a voltage applier that applies a voltage of a predetermined voltage value between the anode and cathode of the replica transistor. In this semiconductor device, the substrate voltage of the replica transistor is the substrate voltage generated by the substrate voltage generating circuit. The substrate voltage generating circuit controls the substrate voltage to be generated so that the current value of the current flowing into the replica transistor becomes equal to a given target value.