A technique of reducing the possibility that the thickness of an adhesive layer in a seal member becomes non-uniform is provided. There is provided a fuel cell comprising a membrane electrode gas diffusion layer assembly; a seal member; and a first separator and a second separator arranged to place the diffusion layer assembly and the seal member therebetween. The seal member includes a first adhesive layer facing the first separator, a second adhesive layer facing the second separator, and a core layer that is placed between, and is harder than, the first and second adhesive layers. Each of the first and second separators includes an opposed surface that faces the corresponding adhesive layer and a convex protruded from the opposed surface in a direction toward the seal member. A circumference of the convex in the opposed surface adheres to the corresponding facing adhesive layer.