LID OPENING/CLOSING DEVICE

A lid opening/closing device includes: a lid box having a housing space in which a supply port is housed and an opening through which the housing space is exposed to a vehicle body outside, the lid box being mounted on a vehicle body; a lid configured to open/close the opening; a seal portion sandwiched between the lid box and the lid and elastically deformed at a closed position of the lid; and a gap placement portion placed at a gap portion formed between an outer edge portion of the lid and the vehicle body at the closed position of the lid, the gap placement portion being spaced apart from the outer edge portion of the lid and in contact with the vehicle body at the closed position of the lid. The gap placement portion is formed of a material that is more water repellent than the vehicle body.