A piezoelectric actuator 10 includes: a piezoelectric element 11; an external electrode 12 covering partially a first surface 11a of the piezoelectric element 11 in a first direction; a wiring member 14; and a conductive joining member 20 joining the wiring member 14 to the external electrode 12, wherein the conductive joining member 20 has an air gap 70 formed between the external electrode 12 and the wiring member 14 in a region overlapping with the wiring member 14 as viewed in the first direction, and wherein the conductive joining member 20 extends to an edge 21 of the external electrode 12 or extends to the first surface 11a of the piezoelectric element 11 beyond the edge 21 of the external electrode 12.