The mechanical seal device comprises a rotating unit (11) and a stationary unit (12) respectively comprising a ring of ceramic material (13, 15) associated with the bottom of a support element (14, 16) of polymeric material shaping a respective sealing face. The rotating unit (11) and the stationary unit (12) are suitable to be coaxially mounted on a shaft (8) of a rotating member (3), in specular position, so that said rings (13, 15) of ceramic material have said seal faces in mutual contact on a plane substantially perpendicular to the axis of the shaft (8).