NOVELTY - The solid polymer electrolyte direct methanol fuel cell comprises a cell including a membrane electrode assembly that includes an anode (23), a cathode (25) and an electrolyte membrane (11) disposed between the anode and the cathode, an anode-side separator having a surface with a fuel flow channel for supplying a fuel to anode, and a cathode-side separator having a surface with an oxidant flow channel for supplying an oxidant to the cathode. The anode includes an anode catalyst layer (12), and an anode diffusion layer (16). The anode diffusion layer is laminated on the anode catalyst layer.    USE - The solid polymer electrolyte direct methanol fuel cell is useful as a power source: for portable small electronic devices such as notebook personal computers, cellular phones and personal digital assistants; in outdoor leisure activities such as camping; for automobiles such as electric scooters; and for home cogeneration systems.    ADVANTAGE - The solid polymer electrolyte direct methanol fuel cell can be economically and effectively manufactured with compact size, less weight, high output density and power generation efficiency, improved fuel utilization efficiency and reduced amount of catalyst and can be operated even at low temperatures.    DETAILED DESCRIPTION - The solid polymer electrolyte direct methanol fuel cell comprises a cell including a membrane electrode assembly that includes an anode (23), a cathode (25) and an electrolyte membrane (11) disposed between the anode and the cathode, an anode-side separator having a surface with a fuel flow channel for supplying a fuel to the anode, and a cathode-side separator having a surface with an oxidant flow channel for supplying an oxidant to the cathode. The anode includes an anode catalyst layer (12), and an anode diffusion layer (16). The anode diffusion layer is laminated on the anode catalyst layer. The anode catalyst layer contains an anode catalyst positioned on one main surface of the electrolyte membrane. The cathode includes a cathode catalyst layer, and a cathode diffusion layer. The cathode catalyst layer contains a cathode catalyst positioned on the other main surface of the electrolyte membrane. The cathode diffusion layer is laminated on the cathode catalyst layer. The fuel flow channel and/or the oxidant flow channel has parallel linear portions. The anode catalyst layer and/or the cathode catalyst layer has belt-like first regions facing the linear portions and a second region positioned between the adjacent first regions. The amount of catalyst present in the first regions per unit area is larger than the amount of catalyst present in the second region per unit area. In the first regions, the amount of catalyst per unit area increases from an end toward a center in a width direction. In the second region, the amount of catalyst per unit area decreases from an end toward a center in a width direction. The largest amount of catalyst in the first regions per unit area is 1.1-2 times of the smallest amount of catalyst in the second region per unit area. The portion of each of the first regions in which the amount of catalyst per unit area is large faces a central part of each of the linear portions in its width direction. The portion of the second region in which the amount of catalyst per unit area is small faces a central part of the surface of the separator between the adjacent linear portions in its width direction. The total width of a pair of the first and second regions is 1-5 mm. The anode diffusion layer and/or the cathode diffusion layer includes a substrate. The substrate comprises conductive fibers, a microporous layer including conductive particles, and a water-repellent resin. The microporous layer is present in contact with the anode catalyst layer or the cathode catalyst layer such that no gaps are formed between the microporous layer and the first regions and between the microporous layer and the second region. The ratio of the total area of the first and second regions to a projected area of the anode catalyst layer or the cathode catalyst layer is 70-100%. The average thickness of the first regions is greater than of the second region. The fuel flow channel and/or the oxidant flow channel is a serpentine flow channel having the linear portions and curved portions for connecting an adjacent pair of the linear portions. An INDEPENDENT CLAIM is included for a method for producing a polymer electrolyte fuel cell.    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic longitudinal sectional view of a structure of a polymer electrolyte fuel cell.    Electrolyte membrane (11)    Anode catalyst layer (12)    Anode diffusion layer (16)    Anode (23)    Cathode. (25)