Patent ID: 8536766

Claim:
A device using a piezoelectric element comprising: a layered piezoelectric element being a layered product formed of a plurality of piezoelectric layers and a plurality of internal electrode layers, said piezoelectric layers and said internal electrode layers being stacked alternately in a direction orthogonal to said layer surface of each piezoelectric layer, said element including an active portion in which each of said piezoelectric layers is sandwiched between a pair of facing internal electrode layers of said internal electrode layers, and an inactive portion which is provided at least at one of ends of said active portion in a direction orthogonal to said layer surface of each piezoelectric layer, and said inactive portion being formed of a single or a plurality of piezoelectric layers that are not sandwiched between said internal electrode layers; and a driven member bonded to one of exposed surfaces of said inactive portion by means of an adhesive, wherein: an inactive portion porosity, which is the porosity of a portion of said inactive portion present in a region having a specific thickness as measured from said bonding surface to which at least said driven member is bonded of said exposed surfaces of said inactive portion, is greater than an active portion porosity, which is the porosity of said piezoelectric layers forming said active portion, and the porosity of a first part of said inactive portion is different from the porosity of a second part of said inactive portion.