Provided is a technique of analyzing particles in real time while collecting and condensing the particles continuously. Gas and/or particles as a detection target substance that are attached to an authentication target 2 are removed by air flow from a blowing region 5. The removed sample is sucked and is condensed and sampled at a sampling region 10, and ions of the sample are generated at an ion source 21 and are then subjected to mass analysis at a mass analysis region 23. Determination of the obtained mass spectrum is made as to the presence or not of a mass spectrum derived from the detection target substance, and a monitor 27 displays a result thereof. Thereby, the detection target substance attached to the authentication target 2 can be detected continuously in real time, promptly and with a less error rate.