Wet friction plate and wet multiple disc clutch device provided with wet friction plate

A method for manufacturing a friction member having a friction slide surface and multiple lubricant oil recessed portions depressed in a recessed shape with respect to the friction slide surface, the friction slide surface and the lubricant oil recessed portions being formed at a surface of a porous layer having multiple hollow portions, said method comprising:

• an original shape formation step of filtering a slurry raw material containing a paper substrate and forming the raw material in a sheet shape;
• a water content rate adjustment step of removing a water content from the sheet-shaped raw material to adjust a water content rate to 90% to 50%;
• a lubricant oil recessed portion formation step of pressing a lubricant oil recessed portion molding die against the sheet-shaped raw material in which the water content rate has been adjusted to 90% to 50% to form the lubricant oil recessed portions;
• a drying step of removing the water content from the sheet-shaped raw material having the formed lubricant oil recessed portions to adjust the water content rate to 10% or less;
• and
• a curing step of impregnating the sheet-shaped raw material in which the water content rate has been adjusted to 10% or less with a thermoplastic resin,
• wherein the lubricant oil recessed portion molding die is formed of metal threads woven in a grid shape or resin threads woven in the grid shape.