A mechanical seal, such as may advantageously be used for an automotive water pump or the like, in which the amount of frictional torque is significantly reduced. The seal includes a follower ring through which a rotary shaft rotatably passes and a seat ring rotated by the shaft. Recesses are formed in the abutting surface of at least one of the two rings, each recess being defined by a forward edge and a rear edge and opening only to the inner circumferential surface of the rings. The forward edge of each recess is inclined from the inner circumferential surface to the rear side in the direction of rotation of the follower ring relative to the seat ring, and the rear edge extends from the outer end of the forward edge along a radial line extending through substantially the center of the shaft.
