To provide a method for manufacturing a friction member having excellent joint performance between backing metal and friction materiel in which rust is hard to be generated when used in bad environments in the market by a simple process in surface treatment processes to the backing metal for the friction member.

In surface-treating the backing metal for the friction member, a washing process by water is conducted after at least one process selected among a degreasing process, a blasting process, and a rust-proofing coating process. For this process, water-soluble rust-proofing agent is contained by 0.01-5.0 wt.% relative to the washing water to provide this method for manufacturing the friction member.