PURPOSE: To raise work efficiency in a power torque wrench in which plural bolts arranged diagonally or mutually adjoining are tightened by transmitting driving force of a common actuator to a pair of wrenches fitted to the respective bolts and thereby tightened the bolts.

CONSTITUTION: A pair of wrenches 1,1' having an insert 12 with a hole 11 to be fitted to a bolt head or a nut 10, of two adjoining bolts are supported rotatably at both ends of a link 4. A piston rod 7,8 of an actuator 1 pivotally attached on its end to tip of a wrench arm 6. Teeth 13 are formed on the outer periphery of the insert 12 so that the insert is fitted to the wrench detachably with a ring spring or the like. Its rotation in one direction is then locked by ratchet teeth 15 provided in the interior of the wrench engaging with the insert teeth 13. Working oil is supplied to and discharged from the actuator 2 through working oil supply and return hoses connected to a double-walled tube swivel, so that the piston 20 moves reciprocally.