PURPOSE: To easily and safely rotate an arm to a desired position in recovery work or the like for an articulated robot.

CONSTITUTION: A casing 46 provided at the rear part of a mounting flange 41 to be mounted on a robot body is provided with an operating shaft 52 slidable in the axial direction and rotatable in the circumferential direction, and a compression sprint 53 is attached so as to energize the operating shaft 52 in the axial direction. The operating shaft 52 is provided with an operating gear 50 engaged with a first gear 21 provided on the robot body and a handle 51, and a lock pin 54 is fixed which can be engaged with an engagement groove 55 formed on the mounting flange 41. Also, this maintenance tool can be so constituted that it is used with a motor attached using a switch for switching lock/unlock of the motor.