The present invention discloses a dust removal device using expansion pressure. A dust removal device using expansion pressure according to one embodiment may comprise an inlet chamber allowing mixed air including dust to flow inside and including an outlet for discharging the dust downward; a dust collecting chamber disposed at a bottom of the inlet chamber and sealed in a state of communicating with the inlet chamber and the outlet to collect the dust discharged through the outlet; a supplying pipe entering into an inside of the inlet chamber and extending toward the outlet to supply the mixed air into the inlet chamber; a first blower providing a blowing force for sucking in the mixed air and supplying the mixed air through the supplying pipe; an air exhaust duct connected to communicate with the inlet chamber to guide air separated from the dust to be discharged to outside, wherein a communication part of the air exhaust duct, which communicates with the inlet chamber, has a certain size allowing the inlet chamber to generate an expansion pressure inside, and a second blower providing a blowing force to discharge the air inside the inlet chamber to the outside through the air exhaust duct, wherein the supplying pipe and the outlet are spaced apart from each other, and a separation distance between the supplying pipe and the outlet is longer than a range that the mixed air propelled from the supplying pipe can reach to, so that the expansion pressure of the mixed air supplied to the inlet chamber accelerates separation action caused by specific gravity difference between the air and the dust.