There are provided a multi-layer piezoelectric element which suppresses damage or separation of an external electrode and improves durability, as well as an injection device and a fuel injection system using the multi-layer piezoelectric element. A multi-layer piezoelectric element includes a stacked body including stacked piezoelectric bodies and internal electrodes, a conductor layer disposed coveringly on a side surface of the stacked body so as to be elongated in a stacking direction of the stacked body to electrically connect with ends of the internal electrodes, which are extended to the side surface of the stacked body, and an external electrode disposed on the conductor layer, one end in the stacking direction of the external electrode being a feeding end, a bonded region of the external electrode which is bonded to the conductor layer in an area near the feeding end being covered with a resin.