The present invention provides: an electroconductive resin composition comprising: (A) a liquid crystal polyester resin capable of forming an anisotropic melt phase, in an amount of 100 parts by weight, (B) a carbodiimide compound in an amount of 0.01 to 30 parts by weight, (C) an electroconductive carbon powder in an amount of 50 to 3,000 parts by weight, and (D) a filler in an amount of 0 to 10,000 parts by weight; a fuel cell separator made of the above electroconductive resin composition; a process for producing the above fuel cell separator; and a solid polymer type fuel cell using the above fuel cell separator. The electroconductive resin composition alleviates the problems of the prior art, can be mass-produced, and is superior in high temperature resistance and hydrolysis resistance.