A fuel cell includes a stack structure composed of fuel cell units with current collectors between the fuel cell units, a casing housing the stack structure, and a gas flow-regulating member provided in a gap between the casing and the stack structure. The fuel cell unit includes: a cell plate which holds at least one cell and has a gas introduction hole for one of fuel gas and air; and a separator plate which has a gas introduction hole for the one of the fuel gas and the air. The casing introduces the other of the fuel gas and the air via a gas introduction portion and flows the other gas to a gas discharge portion. The gas flow-regulating member guides the other gas to the gas discharge portion through the current collectors.