PURPOSE: To enhance position accuracy of spools, by supporting both end parts of mandrels of supplying and winding spools to two sets of cut grooves, provided in both side parts of a cassette, and receiving stepped parts of the spool in its both sides by internal surfaces in both side parts of the cassette.

CONSTITUTION: A cassette 14, parallelly providing in its both side parts a pair of both side cut grooves 14a, 14b, respectively receives supplying and winding spools 12, 13 in both end parts of their mandrels 12a, 13a by the grooves. The supplying spool 12, forming a stepped part with an outer tube in a length within an internal width A of the cassette 14 and to a degree of less looseness, eliminates the displacement in the axial direction.