Disclosed is a gas diffusion layer for a fuel cell that may be made thinner by integrally forming a base and a fine pore layer, and a method for manufacturing the same. A gas diffusion layer for a fuel cell which constitutes a unit cell of the fuel cell includes: a base layer formed by impregnating a first slurry, in which carbon powder and polytetrafluoroethylene (PTFE) are mixed, in the interior of a carbon fiber base; and a fine pore layer formed by coating a second slurry, in which carbon powder and polytetrafluoroethylene (PTFE) are mixed and which has a viscosity that is higher than the viscosity of the first slurry, on a surface of the base layer.