PROBLEM TO BE SOLVED: To provide an electrostatic-type air purifier for electrifying fine particles in the air and attracting and capturing the electrified fine particles with the use of a metal fiber filter that is disposed on the downstream side and is grounded, in which a flow of electrical charges toward the earth side is suppressed as soon as the fine particles are absorbed to a metal fiber surface of the metal fiber filter so that the fine particles remain kept at the metal fiber surface by an electrostatic force and even fine particles with a diameter of 0.5 &mu；m or smaller can be captured.SOLUTION: In the air purifier having a discharge portion which discharges as a result of high voltage being applied to it and electrifies a particle group in the air, and a filter portion which is arranged on the downstream side of the discharge portion, is formed in a cotton-like state with metal fibers tangled together, is electrically grounded and captures the electrified particle group by electrostatic force； a semiconductor membrane is formed on a surface of the metal fibers.【課題】空気中の微粒子を帯電し、その下流側に設けられ、接地された金属繊維製フィルタで帯電した微粒子を引き寄せ捕捉する静電気式の空気浄化装置において、微粒子が金属繊維製フィルタの金属繊維表面に吸着すると、すぐに電荷が接地側に流れることを抑制することで、微粒子を静電気力で金属繊維表面に保持し続け、径が０．５μｍ以下の微粒子であっても捕捉可能な空気浄化装置を提供する。【解決手段】空気浄化装置の流路中に、高電圧が印加され放電して気体中の粒子群に帯電させる放電部と、この放電部の下流側に設けられ、金属繊維を絡めて綿状に形成されると共に電気的に接地され帯電した粒子群を静電気力で捕捉するフィルタ部とを有する空気浄化装置において、前記金属繊維の表面に半導体皮膜を形成する。【選択図】図１
