Provided is a sliding member which includes a plurality of open pores in a sliding surface, which each comprises one or more opening portions having a circularity of 0.24 or more and a circle equivalent diameter of 10 μm to 150 μm. A ratio of the number of open pores having the overlapping degree of 10% or more between the opening portions is 3% or less. Another sliding member includes a plurality of open pores in a sliding surface, which each comprises one or more opening portions having a circularity of 0.24 or more and a circle equivalent diameter of not less than 10 μm nor more than 78 μm. A coefficient of variation of the opening portions satisfies the following equation: 1.03≦√V/X≦1.51 where √V is a standard deviation of circle equivalent diameters, and X is an average value of the circle equivalent diameters. A mechanical seal ring, a mechanical seal and a faucet valve each using the sliding member are also provided.