To provide a method of loading an assembly containing a pair of film containers.

This method is for loading the assembly containing a 1st film container (13) and an additional container having a film of constant length which is wound around one container and extends to the other container (15). (a) The film of a specific length wound around a large roll (152) is prepared and has its free end fitted to a film winder (54); (b) the film winder (54) is turned to wind the film around the winder (54) in a coil shape; and (c) the coil is put in the additional container (15) before or after (b) and passed through a slot and the film winder (54) is removed.