To allow formation of a simple lid lock mechanism body by improving a lid lock structure for a cylindrical opening part.

The lid lock mechanism comprises a throw-in opening part 9 of an upper unit 5 with a lid 11 engaged therewith, a lock cam 33 having a driving shaft 35 and mounted at the predetermined position outside the throw-in opening part 9 of the upper unit 5, a locking claw 16 mounted on one end of the driving shaft 35 and engaged with a locking groove 11b of the lid 11, and a rack member 13b and a solenoid 13a for limiting the rotational direction of the lock cam 33. When the lid 11 is inserted in the throw-in opening part 9 and turned by the predetermined angle in the predetermined direction, the locking claw 16 is engaged with the locking groove 11b of the lid 11, and the rack member 13b limits the reverse rotation of the lock cam 33 at the predetermined position. By limiting the turn of the lid 11 in the reverse direction, the lid 11 can be locked to the throw-in opening part 9 of the upper unit 5.