PURPOSE: To efficiently filter a solution containing a large amount of fine particles and suspension substances by putting a plurality of filtration devices using bundles of a specified number of hollow yarn filtration membranes in a distance each other not to touch accumulated layers each other and making the lower end parts of the filtration devices not have open parts and be movable.

CONSTITUTION: A filtration device is composed using hollow yarn bundles 20 consisting of hollow yarn filtration membranes 1. The number of the hollow yarn membranes 1 is set to be ≤1000 and filled density of the part which is filled with the hollow yarn filtration membranes 1 with almost a uniform density in the transverse cross-section of the hollow yarn bundles 20 is made to be ≥20%. The upper end parts of the hollow yarn bundles 20 are so supported and fixed as to have open parts 3 of the hollow yarn filtration membranes 1 and the lower end parts of them are made not to have open parts and made movable, and a plurality of the filtration devices are put in a container to give a filtration apparatus. In this case, the filtration devices are put in a distance each other in order not to touch the accumulated layers adhering due to the filtration each other easily. A raw liquid 12 is introduced into the hollow yarn bundles 20 and a filtered liquid is obtained in a cap body 22.