The vacuum suctioning unit of the present invention includes: a cover provided with an air entrance; an impeller for circulating air that enters the air entrance; a motor provided with a shaft connected to the impeller; a guide device for guiding the flow of air that exits an exit of the impeller; and a motor housing that houses the motor and is provided with an air exit. The guide device includes: a guide body disposed below the impeller; a first guide vane formed on a side surface of the guide body and guiding air discharged from the impeller; and a second guide vane formed on the bottom surface of the guide body and connected to the first guide vane to guide air that is moved by the first guide vane. The entrance angle of the first guide vane is within the range of 10 to 27 degrees.