An impedance measuring instrument of a fine particle collector comprising a fine particle collection body for collecting fine particles in a fluid, a conductive can body for containing the fine particle collection body, and a buffering body disposed between the fine particle collection body and the conductive can body, wherein two or more electrodes are arranged on the fine particle collection body, at least one of the electrodes is connected with an AC power supply, at least the other electrode is connected with an ammeter, the AC power supply and the ammeter are interconnected and further connected with the conducive can body, and the conducive can body is grounded.