A cell stack device (1) according to the present invention includes a plurality of cells (3) having a columnar shape; and electrically conductive members (4) interposed between adjacent cells (3) of the plurality of cells (3), and connected to the each adjacent cell (3) with a bonding material (15) having electrically conductive property. The bonding material (15) contains electrically conductive particles and fibrous bodies (16) having electrically insulating properties, and a major axis direction of the fibrous bodies (16) is oriented in a predetermined direction in regions where the electrically conductive members (4) face to the each adjacent cell (3).