An inexpensive fuel gas filler structure for a gas-fueled vehicle enables the connection between a ground line and a ground connection portion of the vehicle before the insertion of a fuel gas filler nozzle into a fuel gas filler receptacle. The fuel gas filler structure for a gas-fueled vehicle comprises a fuel gas filler receptacle to which a fuel gas filler nozzle of an external fuel gas filling station is to be connected, a fuel filler lid which is opened or closed, by a fuel filler lid opener, for selectively covering the fuel gas filler receptacle, a ground connection portion to which a ground line of the fuel gas filling station is to be connected, and a ground connection lid which is opened or closed for selectively covering the ground connection portion, wherein an operating section of the fuel filler lid opener is disposed in a region which is covered by the ground connection lid in a closed state.