To provide a manufacturing method of a diffusion layer for a fuel cell enabled to give the diffusion layer desired characteristics.

The manufacturing method of the diffusion layer for a fuel cell comprises (a) a process of preparing ink by dispersing carbon powder and an ionic conductor into a solvent, and (b) a process of forming a catalyst layer and the diffusion layer for the fuel cell by coating ink on a base material by an ink-jet method. First, catalyst layers 122 or 132 are laminated on an electrolyte layer 110 by repeatedly effecting the ink-jet method to form a plurality of catalyst-layer gaps. Next, the ink-jet method is further repeatedly effected to carry out lamination of the diffusion layers 124 or 134 of a desired thickness, and a diffusion-layer gap DS penetrating in a thickness direction are formed. Therefore, an electrode gap ES is formed penetrating the electrodes 120 or 130 in a thickness direction.