A mechanical seal configured to seal an annular gap between a rotating shaft and a housing having a shaft hole for the rotating shaft, the mechanical seal comprising: a fixed ring configured to be fixed to the housing; and a rotating ring unit which includes a rotating ring configured to slide on the fixed ring and to rotate together with the rotating shaft, the rotating ring unit including: an annular elastic seal having a first annular part to which the rotating ring is fitted and thus fixed on an inner circumferential surface side thereof, a second annular part configured to be in close contact with an outer circumferential surface of the rotating shaft, and a curved part which connects the first and second annular parts (131, 133) and is configured to follow a positional change of the second annular part with respect to the first annular part; an annular tightening member configured to tighten an outer circumferential surface of the second annular part on the rotating shaft; and a metal case including an annular fitting part to which the first annular part is fitted and thus fixed on an inner circumferential surface side thereof, wherein the fitting part includes a slipping stopper, the slipping stopper being configured to restrain the first annular part from rotating relatively in the circumferential direction, characterized in that the slipping stopper is a shot blasted part provided on the entire case obtainable by subjecting the entire case to shot blasting processing without masking. a fixed ring configured to be fixed to the housing; and a rotating ring unit which includes a rotating ring configured to slide on the fixed ring and to rotate together with the rotating shaft, the rotating ring unit including: an annular elastic seal having a first annular part to which the rotating ring is fitted and thus fixed on an inner circumferential surface side thereof, a second annular part configured to be in close contact with an outer circumferential surface of the rotating shaft, and a curved part which connects the first and second annular parts (131, 133) and is configured to follow a positional change of the second annular part with respect to the first annular part; an annular tightening member configured to tighten an outer circumferential surface of the second annular part on the rotating shaft; and a metal case including an annular fitting part to which the first annular part is fitted and thus fixed on an inner circumferential surface side thereof, wherein the fitting part includes a slipping stopper, the slipping stopper being configured to restrain the first annular part from rotating relatively in the circumferential direction, characterized in that the slipping stopper is a shot blasted part provided on the entire case obtainable by subjecting the entire case to shot blasting processing without masking. an annular elastic seal having a first annular part to which the rotating ring is fitted and thus fixed on an inner circumferential surface side thereof, a second annular part configured to be in close contact with an outer circumferential surface of the rotating shaft, and a curved part which connects the first and second annular parts (131, 133) and is configured to follow a positional change of the second annular part with respect to the first annular part; an annular tightening member configured to tighten an outer circumferential surface of the second annular part on the rotating shaft; and a metal case including an annular fitting part to which the first annular part is fitted and thus fixed on an inner circumferential surface side thereof, wherein the fitting part includes a slipping stopper, the slipping stopper being configured to restrain the first annular part from rotating relatively in the circumferential direction, characterized in that the slipping stopper is a shot blasted part provided on the entire case obtainable by subjecting the entire case to shot blasting processing without masking.