MULTILAYER PIEZOELECTRIC ELEMENT, AND INJECTION DEVICE AND FUEL INJECTION DEVICE USING THE SAME

[Problem] Provided is a multi-layer piezoelectric element which has no decline in the amount of displacement even under a condition of long-time use, and can protect a surface against adsorption of the content of moisture and impurities, thereby preventing occurrence of short-circuiting. [Solution] A multi-layer piezoelectric element (1) includes a stacked body (7) in which piezoelectric layers (3) and internal electrode layers (5) are alternately laminated in such a way that an end face of each of the internal electrode layers (5) is partly exposed at a side face of the stacked body (7); and a pair of external electrodes (8) that are bonded to side faces of the stacked body (7) so as to make connection with the internal electrode layers (5), wherein a multiplicity of voids (4) exists in the internal electrode layers (5), and the end face of each of the internal electrode layers (5) partly exposed at the side face of the stacked body (7) is substantially free from the voids (4). The stacked body extends straight, and is thus resistant to heat liberation. This makes it possible to avoid decline in the amount of displacement. It is possible to protect the end face of the internal electrode layer (5) against adsorption of the content of moisture and impurities, and thereby prevent occurrence of short-circuiting between the internal electrode layers (5).