PURPOSE: To execute an endless projection, by holding plural mount films by plural windows provided radially on a discoidal disk body so as to be freely attachable and detachable, respectively, loading this disk body in a slide projector, and rotating it.

CONSTITUTION: A mount film 23 is fitted into each window 4, and its surface is held by each pawl 6 and is fixed. When a disk body 1 is pushed in between a ball 12 and a supporting wall 13, the left and right balls 12 are fitted to a circumferential groove 8 and a gear 3 is engaged with a pinion gear 15. When a lamp is lighted, its light irradiates the mount film 23, and is projected onto a screen by a projection lens. When a constant interval of time passes by a timer, etc., a motor is started and the pinion gear 15 is engaged with the gear 3, by which the body 1 turns, and when the following through-hole reaches a position for passing through a beam of a photocoupler, the motor stops and projection is started. In this way, the body 1 executes an intermittent rotation at every constant interval of time and the endless projection is executed.