To provide a device which can sufficiently remove suspended matters without requiring any exchanging work.

This device includes an inlet port, into which a gas containing suspended matters flows, causing whirls of the gas in a casing, a rotary body which further imparts a centrifugal force to the whirls to move the suspended matters in the gas outwards, a small chamber provided outside the outer periphery of the rotary body to collect the suspended matters, and an outlet port provided in opposition to the inlet port.