An all-solid-state battery includes a body including a solid electrolyte layer, and an anode layer and a cathode layer alternately stacked with the solid electrolyte layer interposed therebetween. A first external electrode is disposed on one side of the body and includes a first electrode layer and a first conductive resin layer disposed on the first electrode layer, and a second external electrode is disposed on another side of the body and includes a second electrode layer and a second conductive resin layer disposed on the second electrode layer. A protective layer is disposed on an entirety of an external surface of the body free of the first and second electrode layers and on the first and second electrode layers, and at least one opening is included in a region of the protective layer disposed on at least one of the first electrode layer and the second electrode layer.