Carbon substrate for gas diffusion layer, gas diffusion layer using the same, and electrode for fuel cell comprising the gas diffusion layer

In the thickness direction, porosity of the base material for a gas diffusion layer that represents the gradient, this gas diffusion layer, a fuel cell electrode, a membrane electrode assembly and a fuel cell including the same are provided with. The gas diffusion layer is excellent in both bending strength of the water discharge ability and the MD direction and the CMD direction.