FLEXIBLE CIRCUIT SUBSTRATE, MANUFACTURING METHOD THEREOF, AND FUEL CELL EMPLOYING SAID FLEXIBLE CIRCUIT SUBSTRATE

There is provided a flexible circuit board capable of preventing corrosion and elution of a conductor layer constituting a current collector even under high-temperature and high-voltage working conditions while achieving sufficient electric connection with an MEA. A flexible circuit board having a current collector of a fuel cell provided thereon includes an insulating flexible base material 1, a plurality of openings 5 that supply fuel or air, the openings 5 being provided in a specified region so as to penetrate through the flexible base material 1 in a thickness direction, a plating film 6 that constitutes the current collector, the plating film 6 being formed on front and back surfaces of the flexible base material 1 in the specified region and on inner walls of the openings 5, a surface treatment film 9 formed on the plating film 6 and having corrosion resistance higher than that of the plating film.