In a lid locking device of the present invention, a first rod constituting portion at the front end of a rod is eccentrically located on a side of the rod which is a side spaced away from the lid at a forward extending region of the second rod constituting portion linearly movably supported at the tip cylindrical portion. Therefore, even where an engagement protrusion piece presses a side close to the lid of a tip swelling face of the first rod constituting portion, the device of the present invention is able to receive an axial force F derived from pressing force at a position closer to the central axis of the second rod constituting portion and also decrease in resistance on operation of closing the lid compared to a conventionally structured device.