To conduct analysis under high sensitivity to measure a concentration of polychlorinated-dibenzo-p-dioxins, by adsorbing and concentrating the polychlorinated-dibenzo-p-dioxins contained in gas, fly ashes, active carbon particulates discharged from the municipal refuse incinerator and the like at a speed near to an on-line real time.

At least one of the gas, the fly ashes, the active carbon particulates, containing dioxin, discharged from the municipal refuse incinerator and the like is adsorbed and concentrated onto a sample adsorbing element membrane tube, the membrane tube is fitted to just an underside of a nozzle throat for injection to a vacuum chamber in a mass spectrograph, the membrane tube is irradiated with a pulsed laser beam to separate the adsorbed polychlorinated-dibenzo-p-dioxins, and then the concentration of the polychlorinated-dibenzo-p-dioxins are measured by the mass spectrograph.