PURPOSE: To prevent damage of a rim in fitting and removing a tire by providing the head of a tire replacing device with a low-friction insert unit having contact surfaces abutting to the head, and the front and the peripheral surface of the rim, respectively, and with a means for fixing the insert unit to the head at the abutting portions.

CONSTITUTION: A recess 22 is formed in a fitting and removing head 14, and the main part 24 of a low-friction insert unit 23 formed of nylon or the like is inserted therein and fixed by a set screw 27, By this arrangement, the insert unit 23 is freely removable so as to be replaced when it wears away. A first face 29 and a second face 31 intersecting each other at an angle are formed on the insert unit 23, and the unit is positioned so that the first face 29 comes into contact with the front 19a of a rim 19 and the second face 31 comes into contact with the peripheral surface 19b of the rim 19. By this arrangement, the insert unit 23 and the rim 19 are brought into sliding contact with each other in fitting and removing a tire 21, so that damage of the rim 19 can be prevented, and the head can be replaced at need.