To solve the problems that removal of an external electrode is difficult, and short circuiting is caused by the positional deviations between a piezoelectric body and insulation reinforcing plate.

Electrode patterns 11a (+) and 11b (-) are arranged on the front and rear sides of a laminated piezoelectric body 11, and side electrodes 12a (+) and 12b (-) are arranged on both sides longitudinally. Electrode patterns 13a (+) and 13b (-) of substantially the same shapes as those of the electrode patterns of the laminated piezoelectric body 11, which is to be bonded, are formed on both sides of an insulation reinforcing plate 13, and both pole patterns 14a (+) and 14b (-) for external removal, extending to the outside of the piezoelectric body installed region on the insulation reinforcing plate 13 are arranged. Respective polarity of the both the pole patterns is conducted by the side electrodes 12a (+) and 12b (-) arranged on the laminated piezoelectric body 11. A through-hole 15 is provided to the patterns 14a (+) and 14b (-) for external conduction of the insulation reinforcing plate 13, electrodes on the front and rear sides are bundled, and all the portions between the laminated piezoelectric body 11 from among the electrode patterns, provided to the insulation reinforcing plate 13, are covered by resist film 16. Short circuiting between the piezoelectric body and the insulation reinforcing plate can be prevented.