Provided is a small-sized cylindrical battery in which improvement in battery characteristics and improvement in long-term reliability and safety are both realized. A space for accommodating elastic deformation of the resilient arms is formed among the body and the connecting portions. Alternatively, the plurality of photodiodes have a common cathode and a plurality of separate anodes, and an output of the common cathode is considered to be equivalent to a sum of outputs of a plurality of separate photodiodes. By using the PRO measurement apparatus, the PRO during idling is measured. The logic module is configured to generate a control signal in response to the power-on signal and the brown-out signal.