To provide a piezoelectric actuator and a fluid discharge device capable of suppressing breakage at a boundary portion in a deformation area during driving.

This is a piezoelectric actuator in which a common electrode, a piezoelectric body layer, and a surface individual electrode are layered on a vibration plate and a surface of the vibration plate in this order, and the plurality of surface individual electrodes are formed at the surface of the piezoelectric body layer. The shape of an outer periphery portion of the surface individual electrodes is corrugated or sawtooth shaped. Moreover, it is desirable that a ratio L/L0 of the length L of the outer periphery of the surface individual electrodes to the length L0 of the outer periphery when an area S of the surface individual electrodes is subjected to circle conversion is 1.1 or more.