A mechanical seal wherein a smooth sealing end surface is formed at one end of a rotation seal ring and a stationary seal ring, while a sharp edge-like sealing end portion in slidable contact with the smooth sealing end surface is formed at the other of seal rings, the sealing end portion having a width of 0.1 to 0.3 mm, and the spring face pressure to be imparted to that portion of sealing end portion which slidably contacts with the sealing end surface is set to a relatively high value from 30 to 50 kg/cm.sup.2. Materials of which the sealing end surface and the sealing end portion are made are selected from hard ceramics.