PURPOSE: To prevent effectively the slip in the axial direction at the time of rolling and contact without enlarging an entire device by having the periphery of an epicyclic roller crown formed and constructing an outer wheel deformable along the crown.

CONSTITUTION: The rotational input provided at a holder main body 20 is transmitted to a solar roller 10 at the speed increasing ratio corresponding to the diameter of each roller on the basis of the rolling against the outer wheel 14 of an epicyclic roller 12 so that a tool is rotated at high speed. Then the peripheral surface of the epicyclic roller 12 is crown formed, and the contact part of the outer wheel 14 is deformed along this crown. As a result, the outer wheel 14 presents the behavior similar to the belt being wound on the crown formed pulley, that is, the outer wheel 14 is shifted toward the center part with the large diameter of the epicyclic roller 12 even in attempting to slip in the axial direction out of the epicyclic roller 12 so that the slip can be effectively prevented.