A guide belt (6) is stretched over a drive pulley (4) that rotates integrally with a head (1) and a driven pulley (5) situated at one side of the drive pulley (4). One end (9a) of the cable (6) is fixedly attached to a part of the guide belt (6) that is always in contact with the drive pulley (4) when the head (1) rotates, while the cable (9) is extended along the guide belt (6). The cable is bent back in U shape at its midpoint and the cable on the other end side therefrom is extended along a guide member (8) placed substantially in parallel with the guide belt (6) between the drive pulley (4) and the driven pulley (5). The other end (9b) of the cable (9) is fixedly attached to the guide member (8). <IMAGE>