PURPOSE: To simplify the conveying direction of a tool and to smoothly change of the tool through discrimination of a mounting and a recovery circuit by securing an adapter, in which a through-hole is longitudinally formed, to the base part of the tool, and arranging a feed and a recovery arm so that the arms are reciprocated between a main spindle end and a tool storing device.

CONSTITUTION: An adapter 31 is lifted through drive of a lifting arm 22 by press operation of a hydraulic cylinder 23 and forcibly taken out from a storage device 93. Support levers 52 and 52 of a feed arm 54 are raised as the support arms are inserted in respective through-holes 51 and 51 of the adapter 31. A protrusion 56 of an electromagnetic device 55 of the arm 54 is protruded to hold the adapter so that the adapter 31 is prevented from dropping from the arm 54. During recovery of a tool C cutting of which is completed, the upper and lower arms 54 and a recovery arm 61 are arranged above and below a main spindle 1 again through movement of a conveyance plate 15. A rack 39a is pressed by a hydraulic cylinder 57, and a lock pin flat surface 37a is positioned flush with the side of a guide protrusion part 32. When a wedge 49 is pressed by means of a hydraulic cylinder 59, a tool mounting part 5 and the adapter 31 are released from coupling therebetween.