▎ 摘　　要

NOVELTY - A carbon fiber substrate comprises carbon fibers, a binder and a nanocomposite material. USE - Carbon fiber substrate used for gas diffusion layer for fuel cell (all claimed) e.g. polymer electrolyte membrane fuel cell. ADVANTAGE - The carbon fiber substrate has excellent water-repellent property, and is economically manufactured by simple method. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: gas diffusion layer for fuel cell; manufacture of the carbon fiber substrate treated with nanocomposite material; and manufacture of the gas diffusion layer.