An objective of this invention is to reduce an electric resistance in a separator and to improve its corrosion-resistance, mechanical strength and sealing performance, that leads to improve a fuel cell output and prevent deterioration in a direct methanol type fuel cell with a planar stack structure. The above objective is achieved by using a separator comprising a clad material consisting of a low-resistance material and an anti-corrosive material coating at least the front and the rear surfaces of the low-resistance material, wherein an area except an electric connection on the clad material is coated with an insulating coating layer.