NOVELTY - An adhesive sealing member (10) for use in fuel cell comprises a thermoplastic resin as a main component; and resin particles having a heat-resisting temperature that is higher than melting point of the thermoplastic resin. The adhesive sealing member is formed into film.    USE - As adhesive sealing member for providing sealing in fuel cell (claimed) e.g. polymer electrolyte fuel cell (PEFC), and direct methanol fuel cell (DMFC).    ADVANTAGE - The adhesive sealing member has favorable creep resistance and provides excellent productivity of fuel cells. If the adhesive sealing member is heated and compressed, an amount of displacement in a direction of the compression is suppressed by the resin particles with a higher heat-resisting temperature than the thermoplastic resin, and compressive creep hardly occurs. Therefore, the adhesive sealing member has favorable creep resistance. Since the adhesive sealing member includes the thermoplastic resin as the main component, an adhesive property and a sealing property can be assured within a short period as compared to a conventional adhesive sealing member including thermosetting resin as main component. The adhesive sealing member has low susceptibility to impurities or soils and is excellent in handleability. When the adhesive sealing member is formed into film, bonding of the adhesive sealing member to separators, and frames can avoid complicated positioning process. The formation into film makes it easy to perform continuous processing. Advance lamination of the adhesive sealing member to the frames makes it easier to perform processing. Since sealing in the fuel cell is made by using the adhesive sealing member, excellent productivity is provided as compared to the conventional one. In the adhesive sealing member, the thermoplastic resin can be denatured by acid. By the denaturation, the adhesive sealing member becomes excellent in wettability to a surface of e.g. metal that constituent members of the fuel cell. Thus, adhesive property and sealing property are improved with ease.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic diagram of the polymer electrolyte fuel cell having the adhesive sealing member.    adhesive sealing member (10)    solid electrolyte membrane (20)    frame (22)    stainless separators (24)    polymer electrolyte cell. (26)