PURPOSE: To open or close and invert grippers correctly and accurately, by arranging multiple sets of gripper pairs on a pair of support shafts supported with a pair of bearing members which reciprocates rotatively about the inversion axis line.

CONSTITUTION: Bearing members 65 and 66 are so arranged as to reciprocate rotatively about the inversion axis line 68 with a driving mechanism 33 and a pair of support shafts 13 and 14 are supported therewith. Multiple sets of gripper pairs 15 and 16 are arranged on both the support shafts separately and driving mechanisms 92 and 130 for opening or closing both the grippers are connected to both the support shafts in such a manner as to operate separately. This can simplify the support structure of the grippers and the construction of the driving mechanism.