PURPOSE: To provide a tube cutting-off device which is inexpensive and by which the excellent cutting-off surface of a tube can be obtained.

CONSTITUTION: The device is equipped with a guide member 11 which is formed with an insertion hole 13 and guides a tube to the center portion side end surface of a base stand 12 while guiding it to the insertion hole 13; and a cutter 15 which cuts off the tube by conducting slide contact movement to a cutting-off end surface 17a where the insertion hole 13 of the guide member 11 opens, and the cutter 15 is fitted in inclination in regard to the cutting-off end surface 17a.