USE OF A GAS DIFFUSION LAYER MEMBER IN A SOLID POLYMER FUEL CELL

To provide a gas diffusion layer member with a good RH balance. A gas diffusion layer member for solid polymer type fuel cell use comprising a sheet-shaped gas permeable conductive base material of a thickness of 100 to 250 µm in range, which gas diffusion layer member is characterized in that a moisture vapor transmission rate by the measurement method defined by JIS L 1099:2006 is 1300 to 2000 g/m 2 /h in range.