To solve the problem involved in the time when a sample is introduced from a sample ionizer (ion source) that the sample with insufficient ionization stays in the site other than pores in an introduction part and is deposited as a product material such as oxide or carbide due to the energy such as heat and that the deposited product material causes performance degradation in a mass spectroscope.

In this invention, a mass spectroscope comprises a sample supply source, a sample ionization part which ionizes the sample supplied from the sample supply source, a sample introduction suppression chamber into which the ionized sample ions are introduced, a differential evacuation chamber located on the downstream of the sample introduction suppression chamber, and an analyzer located on the downstream side of the differential evacuation chamber, and the mass spectroscope is provided with electric discharge generation means which generates electric discharge at least in any one of the sample introduction suppression chamber and the differential evacuation chamber. The electric discharge generation means comprises an opposing sample introduction part electrode and a first pore part member (electrode) installed in the sample introduction suppression chamber to face each other, or the first pore part member (electrode) and a second pore part member (electrode) installed in the differential evacuation chamber to face each other.