To provide a dust processing device with a configuration to prevent a problem with ignition due to high temperature dust.

A dust processing device to remove and collect dust from gas containing the same comprises: an exhaust passage provided with a fan to suction the gas; a separation chamber which has one end communicated with the exhaust passage as well as the other end communicated with a suction passage to suction the gas containing the dust and separates the dust from the gas by swirling the gas flowing through the suction passage with suction force of the fan; a dust discharge passage communicated with a lower end of the separation chamber; and a dust collection chamber to collect the dust by accumulating the same flowing through the dust discharge passage. The dust collection chamber has fire extinguish means which includes: a detection section to transmit an electric signal when detecting heat and/or light from the dust flowing into the dust collection chamber; and an extinguishant spraying section to spray a predetermined amount of extinguishant inside the dust collection chamber in response to the electric signal of the detection section.