A phase shifter includes an FET 2a having its drain electrode connected to an input/output terminal 1a; and FET 2b having its drain electrode connected to the source electrode of the FET 2a and its source electrode connected to an input/output terminal 1b; and FET 2c having its drain electrode connected to the source electrode of the FET 2a; and an inductor 3a having its first terminal connected to the source electrode of the FET 2c and its second terminal connected to a ground. It can reduce the insertion loss by narrowing the gate width of the FET 2a, and carries out the phase shift of a high-frequency signal with suppressing the reflection.