A method for filtrating liquid sample such as blood or the like with a filter member utilizing inner vacuum, the same enabling completion of filtration without removing a stopper, and superior in safety and being free from contamination.In collecting and filtrating the liquid sample using a sample collection vessel 1, in which a sample-collecting part 3 containing a filter member 4 is inserted in a vacuumed sample-storing part 2, the sample storing part 2 and sample-collecting part 3 are air-tightly sealed with a stopper 5, the liquid sample such as blood or the like collected in the sample-collecting part 3 is filtrated by the filter member 4. When the filtration stops, a hollow needle 12 is pierced through the stopper 5 and thus the sample-collecting part 3 is communicated with atmosphere, thereby the pressure in the sample-collecting part 3 being enhanced upper than in atmosphere to enable the filtration again.