The present invention relates to a bio-filter that floats and circulates a microorganism filtering medium by using an air dispenser installed on the bottom of a filtering container, and deposits a solid contained in cultivation water in a deposition container below the filtering container as well. More particularly, the present invention relates to an economical and reasonable bidirectional recirculating bio-filter with a solid collecting function, by which cultivation water can be biologically filtered twice in one filtering water container by dividing an interior space of the filtering water container into left and right water container spaces, arranging filtering media and air dispensers in the air container spaces, and installing porous partitions between the water container spaces and a deposition container, the utility due to the arrangement of a filtering system can be doubled by allowing the cultivation water to flow in a bidirectional fashion through the filtering water container, the cultivation performance for microorganisms in the filtering media and the cultivation water filtering performance for sections can be raised, the solid can be efficiently separated and deposited in a process of turning the cultivation water into a U-shape via lower sides of the porous partitions and the partitions, all the deposited filtering media introduced into the water container spaces can be collected and dispersed by installing the pipe type air dispenser in a low bending part while the porous partitions that are the bottom surfaces of the water container spaces are bent into a V-shape or a W-shape. Accordingly, the filtering performance of the cultivation water can be maximized while the bio-filter has a very simple structure.본 발명은 여과수조의 바닥부에 설치된 에어분산기를 이용하여 미생물 여과매질을 부상 및 순환시키는 한편, 사육수중에 포함된 고형물은 여과수조 하부측의 침전조로 침전시킬 수 있도록 한 생물여과조에 관한 것으로서, 더욱 상세하게는 여과수조의 내부공간을 격판에 의하여 좌,우 2개의 수조공간으로 구획시키고, 각각의 수조공간마다 미생물 여과매질과 에어분산기를 배치하며, 각 수조공간과 침전조의 사이에 다공판칸막이를 설치함으로서, 하나의 여과수조 내부에
