A semiconductor device can realizes the stability and the low power consumption, and includes: a depletion-type field-effect transistor Q1 including a gate terminal, a drain terminal and a source terminal; a group III-V heterojunction bipolar transistor Q2 including a base terminal, an emitter terminal electrically connected to the gate terminal and a collector terminal connected to same potential as that of the source terminal; a first resistor connected between the base terminal and the emitter terminal; and a second resistor connected between the base terminal and the collector terminal.