Problems to be solved:To provide a fuel filler port closing apparatus that can be adapted to fuel filling nozzles of various shapes and that excels in operability.Means to solve the problems:Problems are solved through the fuel filler port closing apparatus adapting two-action fuel filling operation. The first action is to open a cover 5 closing an opening 44 of a fuel filler port by pushing a slider 53 with fuel filling nozzle 71, and the second action is to push and open a flapper 3 closing an opening 211 of a nozzle guide.