To provide a power transmitting device capable of being easily assembled.

A pulley 1 supported to the cylindrical projected part A of a compressor so as to be freely rotated, is the pulley made of synthetic resin into the center of which a bearing 2 is inserted. Plural housing parts 3 formed by each rib 1d are provided for the pulley 1, and each rubber connecting member 8 is fitted in the respective housing parts 3. The projected part 8b of each connecting member 8 is fitted in each recessed part 6b formed in a rotation member 6 mounted to a rotating shaft B. When the rotating shaft B is turned out to be in a locked condition while power is being transmitted, since the projected part 8b of the connecting member 8 escapes from the recessed part 6b of the rotating member 6 while being elastically deformed, the transmission of power is thereby intercepted.