A fuel cell case (10) has a fuel cell installation structure (30) to be fixed to a fuel cell (20) and also has a case body (32) to which the fuel cell installation structure (30) is mounted and which receives the fuel cell (20). The fuel cell installation structure (30) includes a seat base (34) fixed to end plates (24, 26) of the fuel cell (20) by a first bolt (82), a seat plate fixed to the case body (32), and an insulation base body (38) for integrating the seat base (34) and the seat plate (36) together in an insulated manner. The insulation base body (38) has a bolt hole (42) into which the first bolt (82) is inserted and also has a neck portion (44) protruding to the outside of the case body (32). The case body (32) has an opening (60) for preventing interference between the case body (32) and the neck portion (44) of the fuel cell installation structure (30) and also has a cover (90) for covering the neck portion (44). Seal members (46, 47, 48) are arranged between the case body (32) and the insulation base body (38).