A cell stack device in the present disclosure includes a cell stack including a plurality of arranged cells, and a first manifold configured to fix a first end of each of the cells with a sealing material and supply reactive gas to the cells. The first manifold includes a frame body configured to fix the first end of each of the cells with the sealing material inside the frame body, and a plate body bonded to a first end portion of the frame body and having a rigidity lower than that of the frame body. A module in the present disclosure includes a housing and the cell stack device housed in the housing. Furthermore, a module housing device in the present disclosure includes an external casing, the module in the external casing, and an auxiliary device configured to operate the module in the external casing.