Provided is a fuel cell apparatus having a gas permeation mechanism for spontaneously controlling the supply amount of oxidizer from a reduced amount to an amount sufficient for normal operation after a reduction process at the time of activation. The fuel cell apparatus includes a control portion for controlling a potential difference between a fuel electrode and an oxidizer electrode to such a value as to reduce an oxide film of a catalyst used in the oxidizer electrode, and a gas permeation mechanism provided in a flow path through which supplied air flows, wherein the gas permeation mechanism includes a member which allows a gas permeation rate to be controlled depending on surrounding environment.
