To shorten the overall length of a compressor where a power transmission device constituting a torque limiter mechanism is mounted.

A rotor 3 with a ring-shaped groove 3a opened in the protruding direction of a rotary shaft B is supported rotatably by a cylindrical projection A of a compressor. A drive side holding member 5 is fixed by rivets in the groove 3a. The rotary shaft B is furnished with a hub 7 whereto a follower side holding member 8 is fixed by rivets. The cylindrical part 8d of this holding member 8 is inserted into the groove 3a and put on the cylindrical part 5b of the holding member 5 with a gap reserved in the radial direction. The two cylindrical parts 5b and 8d are provided with a plurality of recesses 5d and 8e in parts dividing the circumference equally, and an engaging part 12a of a resilient member 12 fitted by pressure is engaged with the recesses 5d and 8e.