NOVELTY - A fuel cell comprises an electromotive portion, an oxidizing-agent inlet tube (52), and a hygroscopic filter (80). The hygroscopic filter is connected to the other end of the oxidizing-agent inlet tube of the reverse side with respect to the electromotive portion. The filter is a container (82) having an inlet port (83). The container is filled with moisture-absorption component (81) supporting a hydroscopic agent in a porous component consisting of a high molecular ester group-containing compound.    USE - As direct methanol fuel cell useful as power supply of electronic devices, such as personal computers.    ADVANTAGE - The fuel cell efficiently carries out absorption-removal of moisture content in air without causing pulverization of hydroscopic agent. Generation of dust by dew-formation in the air-supply pump and rotation components, and generation of drive sound are decreased. The electric-power-generation capability of the electromotive portion is stabilized.    DETAILED DESCRIPTION - A fuel cell comprises an electromotive portion having a cell on which a fuel electrode and an air electrode are laminated on both sides of an electrolyte film, an oxidizing-agent inlet tube (52), and a hygroscopic filter (80). An air-supply pump is connected with the electromotive portion by the oxidizing-agent inlet tube for supplying air as oxidizing agent to the air electrode. The hygroscopic filter is connected to the other end of the oxidizing-agent inlet tube of the reverse side with respect to the electromotive portion. The filter is a container (82) connected to the other end of the oxidizing-agent inlet tube, and has an inlet port (83). The container is filled with moisture-absorption component (81) supporting a hydroscopic agent in a porous component consisting of a high molecular ester group-containing compound of formula: -(-CH2-C(-COOR1)(-CH3)-)x-(-CH2-C(-COOR2)(-CH3)-)y-.    R1,R2=alkyl;    x=20-350;and    y=5-200.    DESCRIPTION OF DRAWING(S) - The figure shows the perspective view of the hygroscopic filter.    Oxidizing-agent inlet tube (52)    Hygroscopic filter (80)    Moisture-absorption component (81)    Container (82)    Inlet port (83)