A multi-layer piezoelectric element comprising: a stacked body comprising: an active section comprising piezoelectric layers and internal electrode layers laminated together, and an inactive section located outside the active section in a stacking direction; an electrically conductive bonding material disposed on a side surface of the stacked body parallel to the stacking direction; and an external electrode plate connected to the side surface of the stacked body with the electrically conductive bonding material interposed therebetween; wherein the external electrode plate comprises: one end extending past the electrically conductive bonding material in the stacking direction, and an area connected to an external circuit on the one end; and characterized in that the electrically conductive bonding material comprises a wider region with a greater width than other regions of the electrically conductive bonding material, at one end thereof closer to the one end of the external electrode plate than to the other end, wherein: a thickness of each of the piezoelectric layers in the active section near a boundary with the inactive section gradually increases as getting closer to the inactive section; and a boundary between the wider region and the other regions of the electrically conductive bonding material is on the piezoelectric layers having an increased thickness. a stacked body comprising: an active section comprising piezoelectric layers and internal electrode layers laminated together, and an inactive section located outside the active section in a stacking direction; an electrically conductive bonding material disposed on a side surface of the stacked body parallel to the stacking direction; and an external electrode plate connected to the side surface of the stacked body with the electrically conductive bonding material interposed therebetween; wherein an active section comprising piezoelectric layers and internal electrode layers laminated together, and an inactive section located outside the active section in a stacking direction; an electrically conductive bonding material disposed on a side surface of the stacked body parallel to the stacking direction; and an external electrode plate connected to the side surface of the stacked body with the electrically conductive bonding material interposed therebetween; wherein the external electrode plate comprises: one end extending past the electrically conductive bonding material in the stacking direction, and an area connected to an external circuit on the one end; and one end extending past the electrically conductive bonding material in the stacking direction, and an area connected to an external circuit on the one end; and characterized in that the electrically conductive bonding material comprises a wider region with a greater width than other regions of the electrically conductive bonding material, at one end thereof closer to the one end of the external electrode plate than to the other end, wherein: a thickness of each of the piezoelectric layers in the active section near a boundary with the inactive section gradually increases as getting closer to the inactive section; and a boundary between the wider region and the other regions of the electrically conductive bonding material is on the piezoelectric layers having an increased thickness. a thickness of each of the piezoelectric layers in the active section near a boundary with the inactive section gradually increases as getting closer to the inactive section; and a boundary between the wider region and the other regions of the electrically conductive bonding material is on the piezoelectric layers having an increased thickness.