A carbon member for use as a battery member of a redox flow battery or a fuel cell, obtained by welding, into a single integrated body: a first layer including a first resin composition containing a polyolefin-based resin and having a melt flow rate of 0.01 to 10 g / 10 min, and a first carbonaceous material; a second layer including a second resin composition containing a polyolefin-based resin, having a melt flow rate of 5 to 1,000 g / 10 min that is greater than that of the first resin composition, and having a melting point that is 80° C. or higher, but is at least 10° C. lower than that of the first resin composition, and a second carbonaceous material; and a third layer, which is disposed facing the first layer with the second layer interposed therebetween, and is formed from a porous carbon material having a specified bulk density.