A motion-picture projector is adapted for the employment of a film cartridge of such a type as containing a film supply reel with the film trailing end secured thereto, and a take-up core with the film leading end secured thereto, which core is separable from the cartridge housing through a recess built up in one end of the cartridge. The housing is preferably made from two molded hair sections, one of which is formed with an opening through which a film rewinding spindle of the projector is engageable with the film supply reel, and the other being provided on the inner surface and at a portion corresponding in position to the opening on one of the half sections with a support for supporting the film supply reel to be held in such a manner that at least a portion of spindle hole of the reel appears in the opening formed on one of two half sections. The cartridge is initially set in a first position in the projector in which the spindle of the projector engages the supply reel, and then transferred to a second position due to rotation of a reel supporting member of the projector having said spindle mounted thereon. In the second position, the take-up core is gripped by a gripper on a take-up transferring member, so that upon the rotation of the take-up core transferring member the take-up core is transferred with the film leading end to a film winding position.