A first transistor has a first terminal and a second terminal. A second transistor has a third terminal, a fourth terminal and a fifth terminal electrically connected to the second terminal of the first transistor during amplification performed by the first transistor. A first bias circuit is electrically connected to the first terminal of the first transistor and supplies a first bias to the first terminal so that a magnitude of the first bias is increased with a rise in circuit temperature. A second bias circuit is electrically connected to the third terminal of the second transistor and supplies a second bias to the third terminal so that the magnitude of the second bias is constantly maintained with respect to changes in the circuit temperature.