This study investigated the electrical properties of the gas diffusion layer (GDL) and the bipolar plates that are key components of a polymer electrolyte fuel cell (PEFC). Observations of the contact condition between the GDL and a bipolar plate under compression showed no noticeable increase in contact area with increasing compression pressure above a level of 0.8 MPa. Contact resistance between the GDL and an Au-coated bipolar plate decreased with increasing Au coverage. However, the decrease in contact resistance relative to Au coverage was small, less than 1 mΩ cm 2 , at coverage of approximately 0.6 or higher. That is presumably attributable to the flow of electrons to the Au contact spot with little voltage loss in the in-plane direction of the GDL. One reason for that is the fact that sufficient contact with the GDL was secured, as indicated by the observation results. Additionally, the in-plane resistance of the GDL was markedly smaller than the contact resistance. The change in contact resistance relative to Au coverage was calculated for GDLs having different in-plane resistivities. The results revealed that the increase in contact resistance relative to Au coverage became smaller as the resistivity of the GDL decreased.