NOVELTY - A fuel cell consists of a pair of catalyst layers and a proton-conducting electrolyte membrane. The catalyst layer comprises a two-phase structure with a catalyst aggregation phase (3) composed of catalyst-supporting carbon material (5) and conduction-aiding carbon material (4), and a gas-dispersing carbon material aggregation phase (1) composed of conduction-aiding carbon material. The catalyst aggregation phase is continuous, and the gas-dispersing carbon material phase is dispersed within the catalyst aggregation phase.    USE - Fuel cell. Uses include but are not limited to transport apparatuses, industrial machines, domestic applications, and consumer application machines.    ADVANTAGE - The fuel cell has a simple system control (as humidity management is easy), high environmental adaptability, and excellent electric-power generation efficiency regardless of the humidity conditions. Internal resistance in the catalyst layer is reduced.    DETAILED DESCRIPTION - A fuel cell consists of a pair of catalyst layers sandwiching a proton-conducting electrolyte membrane. The catalyst layer of the cathode includes a catalytic component, electrolyte material (6), and carbon material. The carbon material comprises a catalyst-supporting carbon material, a conduction-aiding carbon material which does not support the catalytic component, and a gas-dispersing carbon material (2) which does not support the catalytic component. The catalyst layer comprises a two-phase structure with a catalyst aggregation phase composed mainly of the catalyst-supporting carbon material and the conduction-aiding carbon material, and a gas-dispersing carbon material aggregation phase composed mainly of the conduction-aiding carbon material. The catalyst aggregation phase is continuous, and the gas-dispersing carbon material phase is dispersed within the catalyst aggregation phase.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of the aggregation phase structure of the catalyst layer.    Gas-dispersing carbon material aggregation phase (1)    Gas-dispersing carbon material (2)    Catalyst aggregation phase (3)    Conduction-aiding carbon material (4)    Catalyst-supporting carbon material (5)    Electrolyte material (6)