A mass analysis apparatus comprising a first ion source which ionizes a sample and produces sample ions, a second ion source which produces reactant ions having a polarity opposite to the polarity of the sample ions, and a mass spectrometer, wherein said second ion source is provided between said first ion source and said mass spectrometer apart from the axis of a flow of the sample ions discharged from said first ion source and emits reactant ions to the flow of sample ions discharged from said first ion source.