To provide a lock system of a cremorne handle which can prevent the cremorne handle from moving and which does not damage locking parts even when a large force is exerted on the cremorne handle for moving it while a door is locked.

A cremorne mechanism 13 draws the door toward a frame body 12 and brings the peripheral edge of the door into intimate contact with the frame body when the door 11 of an opening 15 is closed. The cremorne mechanism has the cremorne handle 14, a first locking tool 21, a second locking tool 22, a third locking tool 23, and first to third holes 12a to 12c to be engaged. The cremorne handle 14 is attached at the center of the door so that it can rotate, and the first locking tool 21 is connected to the cremorne handle. The second locking tool 22 and the third locking tool 23 are connected to the cremorne handle through the medium of an upper rod 16 and a lower rod 17 respectively. The first to third holes 12a to 12c to be engaged are formed on the frame body opposed to the first to third locking tools and can lock the first to third locking tools. A handle lock means is provided at the upper end of the upper rod for unabling the operation of the cremorne handle when the first to third locking tools are brought into engagement with the first to third holes to be engaged through the operation of the cremorne handle.