To provide a device applied with electrochemical reactions such as a fuel cell wherein a three-phase interface effective for reaction can be formed apart from the contingency or theory of probability.

An electrochemical reaction cell is composed of electrode bases 3 and 5, a solid highpolymer electrolyte film 1 and catalyst particulates 72 in such an arrangement that the catalyst particulates 72 are positioned between the bases 3 and 5 and the film 1, wherein the bases 3 and 5 or the film 1 is furnished on the surface with a plurality of ridges 31 and 51 and a plurality of grooves 32 and 52 formed between the ridges, and the catalyst particulates 72 are jointed with the ridgelines 33 and 53 where the top surface of each ridge intersects the wall surfaces of each groove.