To provide a compact crusher equipped with a pneumatic separator capable of efficiently and continuously separating a light matter and heavy matter in large quantity by a single unit.

The pneumatic separator is constituted of an airtight upright duct for classifying a crushed object by virtue of an upward air flow into a light matter being conveyed upward and a heavy matter falling downward in the duct, a separate duct namely an air flow rate control duct disposed parallel to the upright duct for increasing/decreasing the flow rate of the air flowing upward in the upright duct by virtue of a damper disposed in the lower part of the air flow rate control duct, a heavy matter discharge port disposed below the lower ends of the upright duct and the air flow rate control duct for discharging the heavy matter outside via a wind box and a first openable/closable sealing member or a first rotary valve, a cyclone separator whose inlet port is connected to the upper end of the upright duct, a light matter discharge port disposed at the lower end of the cyclone separator for discharging the light matter outside via a second openable sealing member or a second rotary valve, and an air blower for sucking exhaust air and supplying the above wind box with pressurized air, which air blower is in communication with an air discharge port of the cyclone separator via a return pipe.