A sliding member comprising: a back-metal layer having a back surface and a bonding surface ; and a sliding layer on the bonding surface of the back-metal layer , the sliding layer having a sliding surface , wherein the back-metal layer comprises an Fe alloy, wherein the sliding layer comprises a copper alloy comprising: 0.5 to 12 mass% of Sn; optionally, one or more elements selected from 0.01 to 0.2 mass% of P, 0.1 to 15 mass% of Ni, 0.5 to 10 mass% of Fe, 0.01 to 5 mass% of Al, 0.01 to 5 mass% of Si, 0.1 to 5 mass% of Mn, 0.1 to 10 mass% of Zn, 0.1 to 5 mass% of Sb, 0.1 to 5 mass% of In, 0.1 to 5 mass% of Ag, 0.5 to 25 mass% of Pb, and 0.5 to 20 mass% of Bi; and the balance of Cu and inevitable impurities, wherein the sliding member has a cross-sectional structure perpendicular to the sliding surface , the cross-sectional structure comprising first copper alloy grains that are in contact with the bonding surface and second copper alloy grains that are not in contact with the bonding surface , wherein the first copper alloy grains has an average grain size D1 and the second copper alloy grains has an average grain size D2, these average grain sizes being measured as defined in the description, and D1 and D2 satisfy the following relations: D1 is 30 to 80 μm; and D 1 / D 2 = 0.1 to 0 .3 , wherein, in the cross-sectional structure, the second copper alloy grains comprise third grains that includes internal grains therein that are not in contact with a grain boundary of the third grains , and wherein a total area S0 of the third grains and a total area S2 of the second copper alloy grains satisfy the following relation: S 0 / S 2 = 0.25 to 0.80 . a back-metal layer having a back surface and a bonding surface ; and a sliding layer on the bonding surface of the back-metal layer , the sliding layer having a sliding surface , wherein the back-metal layer comprises an Fe alloy, wherein the sliding layer comprises a copper alloy comprising: 0.5 to 12 mass% of Sn; optionally, one or more elements selected from 0.01 to 0.2 mass% of P, 0.1 to 15 mass% of Ni, 0.5 to 10 mass% of Fe, 0.01 to 5 mass% of Al, 0.01 to 5 mass% of Si, 0.1 to 5 mass% of Mn, 0.1 to 10 mass% of Zn, 0.1 to 5 mass% of Sb, 0.1 to 5 mass% of In, 0.1 to 5 mass% of Ag, 0.5 to 25 mass% of Pb, and 0.5 to 20 mass% of Bi; and the balance of Cu and inevitable impurities, 0.5 to 12 mass% of Sn; optionally, one or more elements selected from 0.01 to 0.2 mass% of P, 0.1 to 15 mass% of Ni, 0.5 to 10 mass% of Fe, 0.01 to 5 mass% of Al, 0.01 to 5 mass% of Si, 0.1 to 5 mass% of Mn, 0.1 to 10 mass% of Zn, 0.1 to 5 mass% of Sb, 0.1 to 5 mass% of In, 0.1 to 5 mass% of Ag, 0.5 to 25 mass% of Pb, and 0.5 to 20 mass% of Bi; and the balance of Cu and inevitable impurities, wherein the sliding member has a cross-sectional structure perpendicular to the sliding surface , the cross-sectional structure comprising first copper alloy grains that are in contact with the bonding surface and second copper alloy grains that are not in contact with the bonding surface , wherein the first copper alloy grains has an average grain size D1 and the second copper alloy grains has an average grain size D2, these average grain sizes being measured as defined in the description, and D1 and D2 satisfy the following relations: D1 is 30 to 80 μm; and D 1 / D 2 = 0.1 to 0 .3 , wherein, in the cross-sectional structure, the second copper alloy grains comprise third grains that includes internal grains therein that are not in contact with a grain boundary of the third grains , and wherein a total area S0 of the third grains and a total area S2 of the second copper alloy grains satisfy the following relation: S 0 / S 2 = 0.25 to 0.80 . <EOS>