Abstract: A safety valve device used for enclosed cells, in which safety valve device an elastic valve body, which has a cross section with not more than eight angles, is placed in a valve chamber formed between a cap type positive terminal and a dish type opening seal member. Owing to the above-described construction, the volume ratio of the elastic valve body to the interior of the valve chamber can be reduced to a low level. Moreover, the valve body is placed in the center of the interior of the valve chamber so as to seal a gas discharge port reliably, and minimize the variation of the safety valve operating pressure.