Patent ID: 7345403

Claim:
A lamination-type piezoelectric element comprising: a ceramic laminated body in which ceramic layers and inner electrode layers are alternately laminated on each other; and a pair of outer electrodes respectively joined to a pair of joining faces formed on an outer circumferential face of the ceramic laminated body, wherein an outer circumferential groove portion coming into contact with an outer circumferential end portion of at least some part of the inner electrode layers is formed at least on the joining faces on the outer circumferential face of the ceramic laminated body, the outer circumferential groove portion has at least one dent portion which recesses inward from the outer circumferential face of the ceramic laminated body, a shape of the dent portion itself or shapes of a plurality of dent portions connected to each other are formed into a belt-shape, the outer circumferential groove portion also has at least one or more protruding portions protruding from the periphery inside the dent portion or the outer circumferential groove portion also has a protruding portion protruding from the dent portion being arranged between the dent portions being adjacent to each other, and at least one of an insulating portion made of insulating material or a conductive portion made of conductive material is formed in the outer circumferential groove portion so that the dent portion can be embedded and the protruding portion can be covered.