To efficiently and easily adjust the unit feed per revolution of a cutting tool holder to a predetermined unit feed per revolution, even though rotational resistance caused at each bearing portion is varied by manufacturing tolerances, errors or the like.

This device is provided with a passive rotor 9 giving corresponding rotation to the unit feed per revolution to a thread-operated feed mechanism D, and also a means E for adjusting slide resistance adjusting the slide resistance between a slidable guide portion 6 and a cutting tool holder 5, by engaging the slidable guide portion 6 guiding a cutting tool holder 5 retaining a cutting tool 2 in the direction of a pipe diameter slidably, a thread-operated feed mechanism D making the cutting tool holder 5 slidable along the said slidable guide portion 6 and an engaging portion 7 provided in a fixing portion next the rotational route of the cutting unit A in the cutting unit A provided with the cutting tool 2 cutting the peripheral wall of an existing pipe along a circumferential direction.