A support member includes a support portion that supports an electric power generation portion of a cell and a seal portion located outside the electric power generation portion and seals between adjacent cells. A seal structure includes outer-side and inner-side wall portions located between adjacent seal portions. The outer-side wall portion is located on a side of an outer circumference of one of the seal portions. The inner-side wall portion is located on another of the seal portions and on a side closer to the electric power generation portion than the outer-side wall portion. An elastic member is provided between the outer-side and inner-side wall portions, and presses the inner-side and outer-side wall portions in opposing directions. A seal member is provided between at least one of the outer-side wall portion and the elastic member, or the inner-side wall portion and the elastic member.