To provide a method of further removing, highly efficiently and with high probability, fine foreign matters such as shell pieces from green laver that has been subjected to removal processing of coarse or medium-sized foreign matters.SOLUTION: A fine foreign matter removing system of this invention includes a step of thinly extending leaf bodies of green laver on an LED light-emitting screening conveyor that is a light transmission device together with low concentration saline water, while causing the green laver to be freely suspended, the green laver having been subjected to removal processing of coarse or medium-sized foreign matters by a conventional technique. The system is configured to enable easy visual distinction of fine foreign matters by contrasting a transmission state of LED light that is transmitted through the thinly extended leaf bodies of green laver, the LED light being illuminated from a bottom surface of the LED light-emitting screening conveyor and a transmission state of LED light that is caused to be transmitted through the fine foreign matters mixed in the green laver.SELECTED DRAWING: Figure 1【課題】粗中異物除去された青のりから更に貝殻片等の微細異物を高効率かつ高確率で除去する方法が無かった。【解決手段】予め従来技術により粗中異物を除去した青のりを自由浮遊させたまま青のりの葉体を、光透過装置であるＬＥＤ発光選別コンベア上に低濃度塩水と共に薄く延ばす。ＬＥＤ発光選別コンベアの下面より照射したＬＥＤ光線をこの薄く延ばした青のりの葉体に透過させたＬＥＤ光線の透過状態と、青のりに混在する微細異物を透過させたＬＥＤ光線の透過状態とを対比することで、微細異物を容易に目視識別できるように構成した。【選択図】図１
