To drive a cleaning mechanism with the rotating power of an exhaust fan and consequently to dispense with an exclusive cleaning motor in the dust collector contg. a cleaning mechanism for sweeping off the dust depositing on a filter bag.

A vibrating rod 18 for oscillating a filter bag 12 is arranged in the case main body 1, and an exhaust fan 6 is set thereabove. A centrifugal mechanism 21 is furnished at the lower end of a fan shift 6a. A flyweight 26 centrifugally oscillated upward is provided to the centrifugal mechanism 21. When the supply of power to the motor of the exhaust fan 6 is stopped, the revolving speed of the fan 6 is gradually lowered. Accordingly, the flyweight 26 is oscillated downward and abutted on a driven protrusion 19 furnished on the upper face of the vibrating rod 18, and the rod 18 is horizontally moved.