The present invention provides a corona discharge device, comprising a first electrode including: a first substantially cylindrical inner chamber portion and a second substantially conical inner chamber portion in communication with the first inner chamber portion, wherein the second inner chamber portion has a cross sectional area that gradually enlarges in a direction away from the first inner chamber portion. The present invention also provides an ion mobility spectrometer comprising: an ionization region; and the corona discharge device disposed in the ionization region. With the above construction and structure, the ion mobility spectrometer of the present invention has the advantages that extraction of ions is facilitated and a life time of the corona electrode is lengthened. In addition, the focusing and storing electrode is used to effectively shield interference of a corona discharge pulse, and to push and focus sample ions. A designed voltage control solution is used to achieve mobility differentiating of ions, while a corona pulse is shielded to prevent variation in an ion quantity due to the corona pulse, thereby achieving an effect of stabilizing mobility spectrum lines.