PURPOSE: To enable a straight moving actuator to generate the action of turning and torsion, by providing a pallet gripper rotary turning device such that a pallet gripper turns 180° by a turning mechanism simultaneously rotates 90° by a rotary mechanism.

CONSTITUTION: A saddle 48 is horizontally moved by actuating an actuator 64, and a vertical gripper 42B reaches a position where it grips a pallet B. If the pallet B is gripped by the gripper 42B, a work table 26 retracts from a head 22. In this way, the pallet B, placed in a condition that it is gripped by the gripper 42B, is detached from a machine tool. Next the actuator 180° turns a pallet clamping arm 41 about a horizontal fixed shaft while 90° rotates both grippers 42A, 42B about the axial center of a gripper shaft through this shaft. Thus the pallet is replaced with each other, further a new pallet is mounted by advancing the work table 26.