The invention discloses a space storage mechanism. The mechanism comprises a movable roller, a fixed roller, an incomplete external gear, an incomplete internal gear, and two or more magazine clip assemblies; the movable roller is coaxially arranged outside the fixed roller, the movable roller and the fixed roller form a rotating pair through a bearing, the two or more magazine clip assemblies arearranged on the periphery face of the movable roller, the incomplete outer gear is arranged on the fixed roller, and is eccentric from the geometric center of the fixed roller, the incomplete internal gear is fixed to the movable roller and is concentric with the geometric center of the movable roller, and an indexing mechanism is formed through the incomplete external gear and the incomplete internal gear. The incomplete external gear is an active part, after the incomplete external gear rotates by a circle, the incomplete internal gear is driven to rotate by the fixed angle, the incompleteinternal gear is locked, meanwhile, the movable roller rotates by the fixed angle, and the magazine clip assemblies reach an output port; storage parts are arranged in the magazine clip assemblies, under the effect of compression springs in the magazine clip assemblies, the storage parts are conveyed to a muzzle. The mechanism is large in capacity and reliable in conveying.