Sliding member and method of manufacturing the same

A sliding member comprising a resin layer that slides with a mating member, wherein

• the resin layer contains polytetrafluoroethylene and an additive spread throughout the resin layer, and
• the resin layer includes a plurality of rich regions having a high concentration of the polytetrafluoroethylene, and a plurality of other regions having a lower concentration of the polytetrafluoroethylene than the plurality of rich regions, and
• the plurality of rich regions and the plurality of other regions are formed in a thickness direction of the resin layer, both the plurality of rich regions and the plurality of the other regions mainly composed of the polytetrafluoroethylene, and an additive contained in the rich regions having a particle size of 5 μm or less,
• when an arbitrary observation field of view is set in a cross section in a plate thickness direction perpendicular to a sliding direction of the mating member in the resin layer,
• a resin depth position P is defined in which an end on the mating member is set to 0 and an end on an opposite side is set to 100 in the thickness direction of the resin layer in the observation field of view, and
• a virtual straight line L is set to be perpendicular to the thickness direction of the resin layer at the resin depth position P in the observation field of view, a total length of the resin layer on the virtual straight line L is defined as D1, a total length of the rich regions on the virtual straight line L is defined as D2, and a rich region proportion R (%) is defined as R=D2/D1×100,
• the rich region proportion R (%) differs depending on the resin depth position P.