To provide a folding knife (1) allowing a user to push out/retract a blade either by the right hand or by the left hand only, to control the blade with a light pressure by fingers and to securely and safely fix the blade when used and stored, and (2) allowing a user to stop the blade in the middle of rotation for storing the blade to prevent the fingers on the handle of the knife from being injured by the edge of the blade.

(1) A disk 9 with grooves 29 and 30 is closely attached to a blade 1, journaled to a handle 2, and temporarily interlocked. The blade 1 is rotated around the disk 9 and a bushing 12 and a notch in the blade 1 are engaged with each other. (2) A notch 23 is formed in a circular opening 28 at the rear end of the blade 1 to be engaged with the bushing 12 in the middle of rotation of the blade 1.