According to the invention, in a separator (4) for a fuel cell which is produced by: loading a complex compound that is configured by bonding graphite powder by means of a thermosetting resin, into a mold (14); and forming ribs (11) for forming gas passages by the resin molding process, the surfaces of the ribs (11) are etched by an alkaline solution or alkali-treated, a surface resin layer which is formed on the surface of the separator (4) is removed away, and graphite particles showing a plate-like form are exposed from the surfaces of the ribs (11) which function as a contact surface with an electrode, whereby the contact resistance with an electrode is remarkably lowered, so that the performance and efficiency of the fuel cell can be improved.