and pierces through a hole 4e of the slide chassis 4 to engage a slot 1e of the main chassis 1 one end of a brake band not shown which is wound around a reel mount is attached to the end of the support lever 8 39 at which the pin 8b 39 is provided tension of the tape 6 imparted by the post 7 39 is adjusted by means of the support lever 8 39 and the brake band a post 9b is erected on a slider 9 the post 9b and the slider 9 jointly constitute a tape wrapping guide for wrapping the magnetic tape 6 around the rotary drum 2 the slider 9 is arranged to slidably engage a separated type guide part consisting of a groove part 3a of the fixed rail 3 39 and a groove part 4f of the slide chassis 4 a first arm 10 rotatably engages the slider 9 through a connection pin 9a a second arm 11 has a toothed part 11c formed along its periphery the second arm 11 is rotatably supported by a support shaft 11a on the main chassis 1 one end of the second arm 11 rotatably engages the first arm 10 through a connection pin 11b a slide gear 12 is rotatably supported by a support shaft 12a on the main chassis 1 and is arranged to be driven by a driving mechanism which is not shown a toothed part 12b of the slide gear 12 is arranged to be capable of engaging the toothed part 11c of the second arm 11 at a part of its circumference a slide pin 12c is erected on a peripheral part of the.