PURPOSE: To enable the cover of a manhole to be easily opened or closed by providing a hook to the key hole in the lower part of the free end of the load point of a lever in a horizontally movable manner and also in bendable manner in the longitudinal direction of the lever.

CONSTITUTION: A key for the manhole cover is made up of a rotary wheel 1 movable back and forth at least and having a slipping preventing face 9 on its periphery, a lever 12 extending in the moving direction of the rotary wheel 1 and having a holder 11 with the rotary wheel 1 as a supporting point on the free end 13 side of its point of application, and a key hole hook 13. The key hole hook 13 is provided in the lower side of the free end side of the load point of the lever 2 in a horizontally movable manner and also in foldable manner in the longitudinal direction of the lever 2. Thus, the cover of the manhole can be easily opened or closed without the need for great amounts of labor and also causing any damage such as intervertebral disk to workers.