A water storage device for a fuel cell system, which includes: a water storage section; and a volume expansion absorber which contracts to absorb volume expansion of water in the water storage section. The axles can ride on a common motor-driven cam between a horizontal orientation to block the skylight and a vertical orientation to allow light to pass. An access procedure is conducted to identify equipment and testing requirements and to establish a communication session between the equipment and an authentication server during an authenticated test. Consequently, a developer-storing container that is easy to assemble and in which precision of interdigitation is high is realized.