Piezo-electric device itself 2 of prism condition outside the edge strip of the said piezo-electric device itself 2 is provided at least with respect to 2 reasons surface electrode , , , the piezoelectric actuator 1 which possesses with , polarization it does outside it is adjacent surface electrode , or , making use of at the time of polarization, when operating the electrode which opposes the fellow, or electrode it impresses police box voltage in the fellow and operates.角柱状の圧電素子本体2と該圧電素子本体2の側面の少なくとも2ヶ所以上に設けられた外部表面電極α,β,γ,δとを有する圧電アクチュエータ1であって、分極時には隣り合う外部表面電極αとγ,δまたはβとγ,δを用いて分極し、動作時には対向する電極αとβ同士、または電極γとδ同士に交番電圧を印加して動作させる。
