A solid-state battery that includes: at least one battery building block including: a positive electrode layer having a positive electrode active material layer; a negative electrode layer having a negative electrode active material layer; and a solid electrolyte layer interposed between the positive electrode layer and the negative electrode layer. The positive electrode layer has a first buffer portion at or adjacent to at least one end of the positive electrode layer, the first buffer portion having a density lower than a density of the positive active material layer in portions other than the at least one end thereof, and the negative electrode layer has a second buffer portion at or adjacent to at least one end of the negative electrode layer, the second buffer portion having a density lower than a density of the negative active material layer in portions other than the at least one end thereof.