Cell stack device, module, and module housing device

A cell stack device comprising:

• a cell stack in which a plurality of cells, each having a cylindrical shape and comprising gas flow passages, are arranged uprightly and are electrically connected;
• a manifold configured to fix lower ends of the plurality of cells and supply gas to the gas flow passages of the plurality of cells;
• and
• a gas supply pipe configured to supply the gas to the manifold;
• wherein
• the gas supply pipe comprises a first end of the gas supply pipe connected to a gas supply portion and a second end of the gas supply pipe inserted into a first through hole in the manifold, and is joined to the manifold via a first joining portion, and
• the gas supply pipe comprises a first protruding portion protruding inwards from an inner side of the gas supply pipe and located at a position corresponding to the first joining portion in any cross-section along an insertion direction of the gas supply pipe into the manifold.