A cell stack device includes a plurality of electrochemical cells, a manifold, a gas supply portion, and a gas collection portion. The manifold includes a gas supply chamber and a gas collection chamber that extend in a direction in which the electrochemical cells are arranged. A support substrate of an electrochemical cell includes a first gas channel and a second gas channel. The first gas channel is connected to the gas supply chamber, and the second gas channel is connected to the gas collection chamber.