A mechanical seal device for use in a water environment includes: a stationary sealing ring made of SiC; and a rotating sealing ring made of SiC and arranged opposite to the stationary sealing ring, the mechanical seal device bringing opposite sliding surfaces of the stationary sealing ring and the rotating sealing ring into close contact with each other to seal a sealed fluid, wherein at least one of the sealing rings including the sliding surfaces is configured by a sintered compact of a material including SiC as a base material compounded with an Al additive, and a specific resistance value of the sealing ring configured by the sintered compact including the sliding surface is equal to or lower than 100 Ω·cm.