<p>A FILTRATION APPARATUS FOR PERFORMING SOLID-LIQUID SEPARATION BY IMMERSING A PLURALITY OF HOLLOW FIBER MEMBRANES (10) IN A TO-BE-TREATED LIQUID (2) CONTAINING A SUSPENDED COMPONENT SO THAT THE TREATED LIQUID PERMEATES THE HOLLOW FIBER MEMBRANES (10). THE FILTRATION APPARATUS INCLUDES THE HOLLOW FIBER MEMBRANES (10) FOLDED DOUBLE; A TREATED LIQUID COLLECTION MEANS COMMUNICATED WITH AN OPEN-SIDE END OF EACH OF THE HOLLOW FIBER MEMBRANES (10); A HOLDING MEMBER (25) FOR HOLDING A BENT PORTION AT AN OTHER-END SIDE OF EACH OF THE HOLLOW FIBER MEMBRANES (10) WITH A GAP FORMED BETWEEN THE BENT PORTION OF EACH OF THE HOLLOW FIBER MEMBRANES (10) AND THE HOLDING MEMBER (25); AND A GAS-JETTING MEANS FOR JETTING A CLEANING GAS FROM THE OTHER-END SIDE OF EACH OF THE HOLLOW FIBER MEMBRANES (10) TO THE OPEN-SIDE END OF EACH OF THE HOLLOW FIBER MEMBRANES (10). A GAP FOR FLOWING THE GAS JETTED BY THE GAS-JETTING MEANS IS FORMED BETWEEN THE HOLLOW FIBER MEMBRANES (10) HELD BY THE HOLDING MEMBER (25) AND THE HOLDING MEMBER (25) OR/AND ON AT LEAST ONE PART OF GAPS BETWEEN THE HOLLOW FIBER MEMBRANES (10).</p>
