lever 82 in one direction around the reference line c with respect to the reference line c which is the axis of the driving side sprocket 43 that is the spacer 84 while allowing the rotation in the other direction around the reference line c that is by rotating the other end portion 82 b of the rotating lever 82 around the reference line c to reciprocate several times in one direction the other direction one direction and the like the driving side sprocket 43 can be rotated in only one direction around the reference line c accordingly the rotation of the driving side sprocket 43 is transmitted and the rotor 14 is rotated to match the phase of the rotor 14 in this example the rotating lever 82 is formed in a bar shape and is rotated on a plane parallel to the reference plane s the rotating lever 82 and the above mentioned fitting and detaching lever 64 are rotated in a direction along the reference line c on the same side with respect to the chain cover 49 in the turning device 80 configured as described above when the operation of the steam turbine is stopped and the control unit 52 is not operated or the like an operator q can operate the rotating lever 82 to rotate the rotor 14 or can operate the fitting and detaching lever 64 to control the position of the pinion gear 46 as described above according to the turning device 80 of this embodiment the coupling guard 70 is prevented from interfering with the chain cover 49 when the coupling guard 70 is attached and detached since.