A mechanical seal having a seal cover that has a high versatility and is less prone to deformation even when secured to a housing by two bolts is provided. A mechanical seal 100 includes a rotating ring 40, a stationary ring 20, and a seal cover 10 to attach the stationary ring 20 to a housing 300. The seal cover 10 includes two U-shaped grooves 11 and two elongate holes 12 for bolting, which are disposed alternately and at regular intervals in a circumferential direction of the shaft hole, and elongate holes 12 are elongate in a radial direction of the shaft hole and innermost positions within the elongate holes 12 where bolt shanks can pass through are located further inward than innermost positions within the U-shaped grooves 11 where bolt shanks can pass through.