Sliding member

A sliding member, comprising:

• a substrate;
• a porous alloy part that is provided on one end surface side of the substrate and that is formed with a Cu-based alloy containing Sn;
• and
• a resin part impregnated in pores formed with the porous alloy part,
• wherein the alloy part and the resin part coexist, and a proportion of the alloy part is large on a side close to the substrate in a thickness direction,
• wherein, in any exposed surface to be exposed by removal from an end surface opposite to the substrate to a side of the substrate, of the alloy part in which the resin part is impregnated, the alloy part and the resin part form a sea-island structure in which the alloy part is distributed as an island-shaped alloy-exposed portion in the resin part as a sea,
• wherein, in the exposed surface, when a surface having a proportion of an area of the alloy-exposed portion in this exposed surface being within a preset set range S is defined as an observation surface, and
• wherein, when any observation region is set in the observation surface, and five inscribed circles with the largest diameters among inscribed circles inscribing each of the island-shaped alloy-exposed portion distributed in the resin part in this observation region are defined as first inscribed circles, all diameters D of the first inscribed circles satisfy 40 μm≤D≤240 μm.