A draw in-out apparatus and an air circuit breaker, the air circuit breaker comprising a cradle electrically connected to an electrical load and an electrical power source, and a main body that is movable to a connected position for being electrically connected to the cradle, a test position at which the main body is electrically disconnected from the cradle but a control power source is connected and a signal input/output is implemented, and a disconnected position at which the main body is electrically disconnected from the cradle, the control power source is not supplied and the signal input/output is not implemented, the draw in-out apparatus for an air circuit breaker comprising: a spindle provided with a thread portion and manually rotatable by being connected to a handle; a movable plate meshed with the thread portion of the spindle by a screw so as to be movable back and forth along the thread portion of the rotating spindle; rack gear installed on an upper surface of the movable plate so as to be movable back and forth along with the movable plate moving back and forth; pinion gear (300a, 300b) installed to be meshed with the rack gear and rotatable according to the rack gears moving back and forth; a cam rotatable by a rotational driving force transferred from the pinion gears by being provided with a teeth portion meshed with the pinion gear provided with a cam slot portion for enduring a load of the main body and a reaction force generated when the main body and the cradle are electrically connected to each other while the main body is moved to a connected position; a pivot disposed on the cradle rotatably supporting the cam; and a driving protruding portion protrudingly extended from the main body or a means for supporting the main body with moving together with the main body and connected to the cam thus to transfer a driving force from the cam to the main body; wherein the pivot is disposed on the cradle at a position adjacent to the middle of a height between electric terminals of the cradle and thus rotatably supporting the cam such that the cam endures the load of the main body and the reaction force generated when the main body and the cradle are electrically connected to each other; characterized in that the cam has a radius larger than those of the pinion gear so as to amplify a torque transferred from the pinion gear. a spindle provided with a thread portion and manually rotatable by being connected to a handle; a movable plate meshed with the thread portion of the spindle by a screw so as to be movable back and forth along the thread portion of the rotating spindle; rack gear installed on an upper surface of the movable plate so as to be movable back and forth along with the movable plate moving back and forth; pinion gear (300a, 300b) installed to be meshed with the rack gear and rotatable according to the rack gears moving back and forth; a cam rotatable by a rotational driving force transferred from the pinion gears by being provided with a teeth portion meshed with the pinion gear provided with a cam slot portion for enduring a load of the main body and a reaction force generated when the main body and the cradle are electrically connected to each other while the main body is moved to a connected position; a pivot disposed on the cradle rotatably supporting the cam; and a driving protruding portion protrudingly extended from the main body or a means for supporting the main body with moving together with the main body and connected to the cam thus to transfer a driving force from the cam to the main body;