A method for evaluating the safety of a battery under an internal short-circuit condition. The method for evaluating an internal short-circuit of a battery is characterized in that a short-circuit can be caused at a desired location inside the battery. According to the evaluation method of the invention, the evaluation result is not affected by the constitution of the outermost part of the battery unlike nail penetration tests which are conventional evaluation methods. Also, unlike crush tests which are conventional evaluation methods, the locations of short-circuits do not vary among tests and the safety under an internal short-circuit condition can be evaluated accurately.