Electric tool with dustproof function

The invention relates to an electric tool with a dustproof function. The electric tool comprises a casing; the casing is internally provided with a motor; a plurality of radiating holes are formed inthe positions, corresponding to the motor, of the casing; the casing is covered with a movable cover which is matched with the rear end of the casing and a handle part in shape; the movable cover is elastically matched with the casing and can move elastically relative to the casing; the movable cover is provided with auxiliary holes matched with the radiating holes in shape and number; in the natural state, the radiating holes and the auxiliary holes are staggered front and back, the radiating holes are closed; in the use state, the radiating holes communicate with the auxiliary holes for heatexchange between air inside and outside the casing; and a dustproof net is arranged at the position, corresponding to the auxiliary holes, of the movable cover. By arranging the movable cover matchedwith the rear end of the c