To surely obtain a μ-V characteristic of positive gradient by distributing many filling materials on a friction surface to reduce a judder phenomenon, in a wet friction material and a method for manufacturing the wet friction material.

Water 2 containing air bubbles 3 having sizes of 5-20 μm is filled in a frame-shaped container 10 spread with a net 11 over a bottom portion by closing the container 10 by a flat plate 12. Next, a fiber material 4 and the filling materials 5 are added to the water 2 containing the air bubbles 3 to be stirred. By still-standing the water 2 for a prescribed time, the fiber material 4 moves upward and the filling materials 5 moves downward to make an unevenly distributed state. By removing the flat plate 12 and dehydrating from the bottom portion, a basic material precursor 6 in which the filling materials 5 are unevenly distributed on a surface of the net 11 at the bottom portion and the fiber material 4 is deposited on the filling materials 5 can be obtained. Thermosetting resin is impregnated in the basic material precursor 6 and the basic material precursor 6 is heated and hardened, and thereby a friction material base material for the wet friction material can be manufactured without causing falling of the filling material 4 and clogging.