LID DEVICE

A lid device to be mounted on an oil filler port or an power supply port of a vehicle and for opening and closing the oil filler port or the power supply port includes a housing configured to be assembled to the oil filler port or the power supply port, a support body provided to be rotatable with respect to the housing, and a lid body attached to the support body. Reinforcing rib protruding toward a lid body side is formed on the support body. A portion of the reinforcing rib along a horizontal direction is inclined such that free end side faces downward when the lid device is mounted on the oil filler port.