To suppress intrusion of discharged water to a lid lock mechanism and to prevent contamination of the lid lock mechanism.

The lid lock water-proofing structure is provided with an upper unit 5 having a throwing opening 9 with which a lid body 11 is engaged; a water discharge passage 94 having a predetermined slope and provided on a periphery of the throwing opening 9 of the upper unit 5; an upper lid lock mechanism 12 provided at a position in the upstream of the water discharge passage 94 and locking the lid body 11; and an annular perforated dish 95 covered along the water discharge passage 94 including the upper lid lock mechanism 12. The perforated dish 95 has a hole part 95a for passing water through the water discharge passage 94; and a non-hole part 95b in which the hole is closed and water is not passed. The non-hole part 95b is set to a position covering an upper area of the upper lid lock mechanism 12. According to the constitution, intrusion of discharged water to the upper lid lock mechanism 12 can be suppressed by the non-hole part 95b of the perforated dish 95 and contamination of the upper lid lock mechanism 12 can be prevented.