FUEL CELL DEVICE

A fuel cell device includes: a cell stack (102S); a case (500) including a cover portion (503) that covers one of side surfaces of the cell stack (102S) along a stacking direction; an end plate (190) connected to one end portion of the cover portion (503) in the stacking direction; and a fastening member (300) that extends in parallel with the stacking direction on an opposite side of the cell stack (102S) from the cover portion (503), that includes one end portion in the stacking direction connected to the end plate (190) and another end portion in the stacking direction connected to the case (500), and that fastens the cell stack (102S), the end plate (190), and the case (500) to each other. A thermal expansion coefficient of the cover portion (503) is larger than a thermal expansion coefficient of the fastening member (300).