A multi-layer piezoelectric element, comprising: a stacked body comprising an active section composed of a stack of piezoelectric layers and internal electrode layers, and inactive sections disposed at opposite ends in a stacking direction of the active section; an electrically-conductive bonding material disposed on a side surface of the stacked body, the electrically-conductive bonding material extending from the active section to the inactive sections; and an external electrode plate attached, through the electrically-conductive bonding material, to the side surface of the stacked body, and wherein the electrically-conductive bonding material is configured so that the electrically-conductive bonding material situated between the side surface of the stacked body of at least one of the inactive sections disposed at the opposite ends and the external electrode plate is larger in thickness than the electrically-conductive bonding material situated between the side surface of the stacked body of the active section and the external electrode plate, characterized in that the external electrode plate is configured so that a spacing between a side surface of the stacked body of at least one of the inactive sections disposed at the opposite ends of the active section and the external electrode plate is wider than a spacing between a side surface of the stacked body of the active section and the external electrode plate, and the external electrode plate is curved so that the spacing between the side surface of the stacked body and the external electrode plate in the active section becomes narrowest at the center in the stacking direction of the stacked body. a stacked body comprising an active section composed of a stack of piezoelectric layers and internal electrode layers, and inactive sections disposed at opposite ends in a stacking direction of the active section; an electrically-conductive bonding material disposed on a side surface of the stacked body, the electrically-conductive bonding material extending from the active section to the inactive sections; and an external electrode plate attached, through the electrically-conductive bonding material, to the side surface of the stacked body, and wherein the electrically-conductive bonding material is configured so that the electrically-conductive bonding material situated between the side surface of the stacked body of at least one of the inactive sections disposed at the opposite ends and the external electrode plate is larger in thickness than the electrically-conductive bonding material situated between the side surface of the stacked body of the active section and the external electrode plate, characterized in that the external electrode plate is configured so that a spacing between a side surface of the stacked body of at least one of the inactive sections disposed at the opposite ends of the active section and the external electrode plate is wider than a spacing between a side surface of the stacked body of the active section and the external electrode plate, and the external electrode plate is curved so that the spacing between the side surface of the stacked body and the external electrode plate in the active section becomes narrowest at the center in the stacking direction of the stacked body.