PURPOSE: To form plural kinds of bits and to make them usable with the bits shaft being changed, by densely passing plural bit forming element shafts in plate/angular/round shapes through a cross shape hollow shaft, and moving plural induction cylinders with the rotation operation of the induction cylinder operation cylinder fitted with plural projections at the inside at the end of the bit forming shaft.

CONSTITUTION: An induction cylinder 19 directly acting on a bit formation is set in the induction cylinder operation cylinder 11 existed in a driver handle. The respective induction cylinder 19 is of the structure that the bit forming shaft 25 only related to the work of its own being fixed to itself and the bit shaft excepting it is passed through itself without exception. This induction cylinder 19 is fixed to the induction cylinder 11, by the rotation of the induction cylinder operation projection on the induction groove 21 on the induction cylinder 11 when the induction cylinder operation cylinder 11 is rotated, without the rotation of this induction cylinder 19, a bit shaft 18 is moved vertically to form the bit.