MANUFACTURING METHOD OF GAS DIFFUSION LAYER WITH MICROPOROUS LAYER, AND MANUFACTURING METHOD OF FUEL CELL

A manufacturing method of a gas diffusion layer with a microporous layer includes coating a gas diffusion layer containing titanium with a precursor containing an electroconductive material, a water-repellent resin, and a polyethylene oxide, and heating the gas diffusion layer coated with the precursor to form a microporous layer containing the electroconductive material and the water-repellent resin on a surface of the gas diffusion layer. The heating atmosphere is a non-oxidation atmosphere where an oxygen concentration is no more than 0.3% by volume.