To provide a compressor that can make a greater range for selection of a rotational speed of an inverter motor, while avoiding resonance of torque variable frequency of an inverter motor and torsional eigenvalue of a shafting system.

In an actual rotation speed R acquired from a motor 20, the connection of a compressor body 10 and a rotation disk 30 is switched to disconnection in order to avoid the matching of the characteristic of frequency fluctuation in torque of a motor 20 (inverter) with the characteristic frequency (second characteristic frequency) while the compressor body 10 and the rotary disk 30 are not connected through a clutch 40 or the characteristic frequency (first characteristic frequency) while the compressor body 10 and the rotary disk 30 are connected through a clutch 40. Optionally, a control section 50 commands the clutch 40 to switch from disconnection to connection between the compressor body 10 and the rotary disk 30.