To shorten preparation time for a sample, and analyzing time of stuck matters in gas mass spectrometry.

A temperature-up separation part 5 wherein, in a quartz chamber 3 supplied with nitrogen gas 2 which can be ionized, a semiconductor wafer 1 is heated for a sticking material to be temperature-up-separated so that separation gas 4 is formed, and the first ion forming part 6 wherein positive ionization of the separation gas ion discharged from the quartz chamber 3 is performed under atmosphere are provided, in addition, the first mass spectrometry part 7 which performs mass spectrometry with positive ion, and the second ion formation part 10 wherein, negative ionization, under atmosphere, is performed with mixture separation gas 9 formed by supplying the separation gas 4 discharged from the quartz chamber 3 with oxygen gas which can be gas ionized are provided. Further, the second mass spectrometry part 11 which performs mass spectrometry with negative ion is provided, so that, positive/negative ionization is, with the use of the same separation gas 4, performed at the first ion formation part 6 and the second ion formation part 10 at the same time, for simultaneous mass spectrometry of both positive/negative ions.