To provide a gas diffusion layer which is excellent in resistance to flooding and plugging, excellent in dry-up resistance and capable of exhibiting high power generation performance over a wide temperature range from low temperature to high temperature and furthermore excellent in mechanical characteristics, conductivity and thermal conductivity.

A fuel cell gas diffusion layer is formed by adjoining and arranging a microporous part [A], an electrode substrate and a microporous part [B] in this order. A carbonaceous powder constituting the microporous part [A] includes carbon nanotubes whose average diameter is 1 to 1000 nm and a carbonaceous powder constituting a microporous part [B] includes granular carbon whose particle size is 3 to 500 nm.