A piezoelectric actuator comprising: a substrate ; a first piezoelectric device and a second piezoelectric device formed at the substrate so as to be arranged side by side along a first direction in the plane of the substrate, the first piezoelectric device including a first lower electrode formed at the substrate, a first piezoelectric body formed at the first lower electrode, and a first upper electrode formed at the first piezoelectric body, the second piezoelectric device including a second lower electrode formed at the substrate in a region different from the first lower electrode, a second piezoelectric body formed at the second lower electrode, and a second upper electrode formed at the second piezoelectric body; a common electrode formed at the substrate and coupled to the first upper electrode and the second upper electrode; and an insulating layer located between the common electrode and the first lower electrode and between the common electrode and the second lower electrode, wherein a side surface of the first lower electrode is not covered with the first piezoelectric body, and a side surface of the second lower electrode is not covered with the second piezoelectric body, wherein a first lead electrode is coupled to an end of the first lower electrode in a second direction in the plane of the substrate perpendicular to the first direction, a second lead electrode is coupled to an end of the second lower electrode in the second direction in the plane of the substrate perpendicular to the first direction, and the common electrode covers each of the first piezoelectric body and the second piezoelectric body on all side surfaces of the first piezoelectric body and the second piezoelectric body other than the side surface of the first piezoelectric body facing the first lead electrode and the side surface of the second piezoelectric body facing the second lead electrode. a substrate ; a first piezoelectric device and a second piezoelectric device formed at the substrate so as to be arranged side by side along a first direction in the plane of the substrate, the first piezoelectric device including a first lower electrode formed at the substrate, a first piezoelectric body formed at the first lower electrode, and a first upper electrode formed at the first piezoelectric body, the second piezoelectric device including a second lower electrode formed at the substrate in a region different from the first lower electrode, a second piezoelectric body formed at the second lower electrode, and a second upper electrode formed at the second piezoelectric body; a common electrode formed at the substrate and coupled to the first upper electrode and the second upper electrode; and an insulating layer located between the common electrode and the first lower electrode and between the common electrode and the second lower electrode, wherein a side surface of the first lower electrode is not covered with the first piezoelectric body, and a side surface of the second lower electrode is not covered with the second piezoelectric body, wherein a first lead electrode is coupled to an end of the first lower electrode in a second direction in the plane of the substrate perpendicular to the first direction, a second lead electrode is coupled to an end of the second lower electrode in the second direction in the plane of the substrate perpendicular to the first direction, and the common electrode covers each of the first piezoelectric body and the second piezoelectric body on all side surfaces of the first piezoelectric body and the second piezoelectric body other than the side surface of the first piezoelectric body facing the first lead electrode and the side surface of the second piezoelectric body facing the second lead electrode. <EOS>