A solid electrolyte battery incorporating a positive electrode with an elongated positive-electrode collector having two sides on which positive-electrode active material layers are formed, a negative electrode with an elongated negative-electrode collector having two sides on which negative-electrode active material layers are formed, and a solid electrolyte layer formed between the positive electrode and the negative electrode such that the positive electrode and the negative electrode are laminated and wound. A ratio A/B of the total film thickness A of the positive-electrode active material layers with respect to the total thickness B of the negative-electrode active material layers satisfies a range from 0.5 to 1.2.