The collecting filter can capture and collect various chlorinated organic compounds in both particulate form and gaseous form contained in a fluid at the same time, and is easy to extract the collected chlorinated organic compounds therefrom. This collecting filter 7 is provided with a fluid-permeable molded body containing fibers and an inorganic binder for binding the fibers to one another, and a hydrophobic material having higher hydrophobicity than that of the fibers and the inorganic binder, which is retained in the molded body. When the collecting filter 7 is disposed in a holder 6 having a discharging path 12a, and a sample gas containing various chlorinated organic compounds is flown into the holder 6 from a flue 25 via a collecting tube 2 and an introducing tube 8, the various chlorinated organic compounds such as dioxins in both particulate form and gaseous form contained in the sample gas are captured and collected upon passage through the collecting filter 7, and the sample gas is discharged through the discharging path 12a to the outside.