A sliding member comprising: a steel back metal layer; and a sliding layer on the steel back metal layer, the sliding layer including a porous sintered layer and a resin composition, wherein the porous sintered layer includes a Ni-P alloy part and Fe or Fe alloy granules, wherein the Ni-P alloy part functions as a binder for binding the Fe or Fe alloy granules with one another and/or for binding the Fe or Fe alloy granules with the steel back metal layer, and wherein the steel back metal layer is made of a carbon steel including 0.05 to 0.3 mass% of carbon, and comprising: a non-austenite-containing portion in a central portion in a thickness direction of the steel back metal layer, the non-austenite-containing portion having a structure of a ferrite phase and pearlite, and an austenite-containing portion in a surface portion of the steel back metal layer facing the sliding layer, the austenite-containing portion having a structure of a ferrite phase, pearlite and an austenite phase, wherein the ratio of the pearlite in the austenite-containing portion is at least 25% less than the ratio of the pearlite in the non-austenite-containing portion, wherein the Ni-P alloy part has a composition comprising: 9 to 13 mass% of P; optionally one or more selected from 1 to 4 mass% of B, 1 to 12 mass% of Si, 1 to 12 mass% of Cr, 1 to 3 mass% of Fe, 0.5 to 5 mass% of Sn and 0.5 to 5 mass% of Cu; and the balance of Ni and inevitable impurities, wherein the ratio of the Ni-P alloy part in the porous sintered layer is 5 to 40 parts by mass in relation to 100 parts by mass of the porous sintered layer, wherein the porous sintered layer includes pores which are impregnated with the resin composition, the porosity thereof being 10% to 60%, wherein the ratio of pearlite in the non-austenite-containing portion is not more than 30 volume%, and wherein the ratio of the Ni-P alloy part in the porous sintered layer is 5 to 30 parts by mass a steel back metal layer; and a sliding layer on the steel back metal layer, the sliding layer including a porous sintered layer and a resin composition, wherein the porous sintered layer includes a Ni-P alloy part and Fe or Fe alloy granules, wherein the Ni-P alloy part functions as a binder for binding the Fe or Fe alloy granules with one another and/or for binding the Fe or Fe alloy granules with the steel back metal layer, and wherein the steel back metal layer is made of a carbon steel including 0.05 to 0.3 mass% of carbon, and comprising: a non-austenite-containing portion in a central portion in a thickness direction of the steel back metal layer, the non-austenite-containing portion having a structure of a ferrite phase and pearlite, and an austenite-containing portion in a surface portion of the steel back metal layer facing the sliding layer, the austenite-containing portion having a structure of a ferrite phase, pearlite and an austenite phase, wherein the ratio of the pearlite in the austenite-containing portion is at least 25% less than the ratio of the pearlite in the non-austenite-containing portion, wherein the Ni-P alloy part has a composition comprising: 9 to 13 mass% of P; optionally one or more selected from 1 to 4 mass% of B, 1 to 12 mass% of Si, 1 to 12 mass% of Cr, 1 to 3 mass% of Fe, 0.5 to 5 mass% of Sn and 0.5 to 5 mass% of Cu; and the balance of Ni and inevitable impurities, wherein the ratio of the Ni-P alloy part in the porous sintered layer is 5 to 40 parts by mass in relation to 100 parts by mass of the porous sintered layer, wherein the porous sintered layer includes pores which are impregnated with the resin composition, the porosity thereof being 10% to 60%, wherein the ratio of pearlite in the non-austenite-containing portion is not more than 30 volume%, and wherein the ratio of the Ni-P alloy part in the porous sintered layer is 5 to 30 parts by mass a non-austenite-containing portion in a central portion in a thickness direction of the steel back metal layer, the non-austenite-containing portion having a structure of a ferrite phase and pearlite, and an austenite-containing portion in a surface portion of the steel back metal layer facing the sliding layer, the austenite-containing portion having a structure of a ferrite phase, pearlite and an austenite phase, wherein the ratio of the pearlite in the austenite-containing portion is at least 25% less than the ratio of the pearlite in the non-austenite-containing portion, wherein the Ni-P alloy part has a composition comprising: 9 to 13 mass% of P; optionally one or more selected from 1 to 4 mass% of B, 1 to 12 mass% of Si, 1 to 12 mass% of Cr, 1 to 3 mass% of Fe, 0.5 to 5 mass% of Sn and 0.5 to 5 mass% of Cu; and the balance of Ni and inevitable impurities, wherein the ratio of the Ni-P alloy part in the porous sintered layer is 5 to 40 parts by mass in relation to 100 parts by mass of the porous sintered layer, wherein the porous sintered layer includes pores which are impregnated with the resin composition, the porosity thereof being 10% to 60%, wherein the ratio of pearlite in the non-austenite-containing portion is not more than 30 volume%, and wherein the ratio of the Ni-P alloy part in the porous sintered layer is 5 to 30 parts by mass