Fine particle measuring equipment

[PROBLEMS] To realize both differentiation mode and integration mode by one DMA and to eliminate the influence of multivalent charging at the time of measuring at the integration mode. [MEANS FOR SOLVING PROBLEMS] In a favorable configuration, at the differentiation mode, a classified charged particle extracting portion (12) is connected to a detector (40), a large diameter particle exhausting portion (13) is closed, a band charged particle extracting portion (35) is connected to a sheath gas supply channel (50), and the voltage between opposite electrodes (3, 4) is varied in such a manner that the diameter of charged particles entering an intake port (12a) for the classified charged particle extracting portion may be scanned. At the integration mode, the band charged particle extracting portion (35) is connected to the detector (40), the classified charged particle extracting portion (12) is closed, the large diameter particle exhausting portion (13) is connected to the sheath gas supply channel (50), and the voltage between the opposite electrodes (3, 4) is kept constant so that charged particles having a predetermined range of diameter may be extracted to the band charged particle extracting portion (35).