FILTER

PURPOSE:To obtain a small-sized inexpensive and simple disposable type filter performing filtering with high reproducibility, by mounting an outer cylinder closed at the bottom part thereof receiving an exuded filtrate and an inner cylinder having a filter mounted to the cylindrical bottom thereof and a seal part, which slides in a state closely contacted with the inner surface of the outer cylinder, provided to the outer surface thereof. CONSTITUTION:In such a state that an inner cylinder 2 is set in an outer cylinder 1 in a deeply inserted state, a specimen to be filtered is injected in the inner cylinder 2. Next, the inner cylinder 2 is drawn up to the direction withdrawn from the outer cylinder 1 corresponding to the amount of the specimen. Whereupon, the space 5 formed by the bottom part of the outer cylinder 1 and the filter 3 and seal part 4 of the inner cylinder 2 is reduced in pressure to be brought to a negative pressure state and, therefore, the specimen to be filtered is filtered through the filter 3. In this case, the quantitative property capable of constant filtering always generating the same result in a constant amount of the specimen to be filtered is provided and an excellent characteristic rich in reproducibility not obtained in a filter based on a press theory is obtained.