the present invention provides a compact horizontal air filter . the electrode array of the elements tending to be tainted with dust in the air filter is simple and convenient to generate clean and fresh air . the air filter comprises a case , a frame slidably inserted in and drew out of the case , a first array electrode fixed on the frame , a second array electrode fixed on the frame and being apart from the first array electrode , and a high voltage pulse generator . the electropositive particles in the air are attracted by the electronegative metal made collecting dust vane when they pass through a collecting dust chamber .