To provide a piezoelectric actuator unit to inexpensively and efficiently perform adhesion with high position accuracy, and also to provide a method for manufacturing the unit, and a supporting case.

The piezoelectric actuator unit includes a rectangular piezoelectric actuator 110 to be bent and displaced by a voltage input, resin-made supporting parts 120, 130 where the longitudinal both ends of the piezoelectric actuator 110 are embedded by integral molding, and a resin-made mobile part 140 which is fixed by integral molding to the longitudinal center part of the piezoelectric actuator 110. The supporting parts 120, 130 and the mobile part 140 are integrally molded with the piezoelectric actuator 110, thereby skipping manual processing work and reducing a cost. Besides, the dispersion of an adhesion position by manual processing is reduced and the position accuracy in the adhesion part is improved. Consequently, the piezoelectric actuator unit 100 with high accuracy is provided at a low cost.