A fuel cell module, wherein slopes of a same angle θ relative to a bottom face are formed on both side faces to form a recessed groove in a tapered shape. Since the angle θ is provided to the side faces of the recessed groove, the exhaustion of gases from the accumulation of gasses to the outside can be assisted by the side faces with the angle θ more than in a case where the side faces of the recessed groove are formed in right angled shapes even if the accumulation of gases is produced between an adhesive agent and the inner surfaces of the recessed groove when first and second separators are joined to each other for modularization by covering the first separator on the second separator. Thus, the accumulation of the gases can be prevented from occurring.