In an exemplary embodiment, a mechanical seal for sealing a fluid flowing outwardly radially from sliding surfaces S where a stationary ring 221 and a rotating ring 211 slide against each other, includes: a bellows 222 interposed between the stationary ring 221 and a stationary wall 226; a case member 223 for holding an outer cylindrical part 222c of the bellows 222 to the stationary ring 221; and a holding member 224 fitted to an inner cylindrical part 222a of the bellows 222, and having an axial length substantially equal to a length fitted to the inner cylindrical part 222a, wherein the bellows 222 has a curved part 222b between the outer cylindrical part 222c and the inner cylindrical part 222a, and the case member 223 is provided with a wall part 223a covering the entire periphery of the radial outer side of the curved part 222b.