An ink jet printer head including a cavity unit; an piezoelectric actuator; and a wiring substrate. The piezoelectric actuator includes pairs of first common electrode connection pads and pairs of first individual electrode connection pads which are provided on an outer surface thereof such that the two first common electrode connection pads of each of the pairs are located at respective positions symmetric with each other with respect to a first reference point on the outer surface and the two first individual electrode connection pads of each of the pairs are located at respective positions symmetric with each other with respect to the first reference point. The wiring substrate further includes a second common electrode connection pad and a plurality of second individual electrode connection pads which are provided at respective positions assuring that when the wiring substrate takes a first angular phase about a second reference point corresponding to the first reference point, and when the wiring substrate takes a second angular phase differing from the first angular phase by 180 degrees about the second reference point, the second common electrode connection pad is electrically connected to at least one of the first common electrode connection pads and the second individual electrode connection pads are electrically connected to the first individual electrode connection pads, respectively.