A dust-removing device is used for removing dust from dust-containing air in a working space, and comprises a dust-preventing mechanism, a spraying mechanism and a recycling mechanism, wherein the dust-preventing mechanism forms the working space; the spraying mechanism comprises a spraying head; the spraying head is installed on the dust-preventing mechanism and used for spraying water mist into the dust-preventing mechanism; the recycling mechanism is arranged below the dust-preventing mechanism and communicated with the dust-preventing mechanism to recycle water mist bonded with dust. The dust-removing device directly sprays water mist into the working space through the spraying mechanism, so that dust generated in the working process is directly bonded with water mist in the working space, dust discharge out of the working space through an exhaust pipe is avoided, and blockage of the exhaust pipe due to accumulation of dust in the exhaust pipe is avoided. Therefore, when the dust-removing device is used, the exhaust pipe is not required to be cleaned and the dust content of air can be effectively reduced.