An agitating mill, particularly an agitating ball mill, comprising a housing having an inlet for material to be ground and for air, an outlet for fines and air, and at least one horizontal agitator shaft which is provided with agitating members. The outlet for fines and air has a large area and is provided in the top wall of the housing and extends throughout the length and width of the top wall of the housing. A plurality of agitator shafts are preferably provided which are juxtaposed and superposed.