PROBLEM TO BE SOLVED: To provide a method for safely and efficiently cutting off cellular tissue of a mucosal layer.SOLUTION: A muscular layer 87 has a submucosal layer 88 stacked thereon, on which a mucosal layer 89 is stacked, and a tumor 92 is cut off from within the mucosal layer 89. At this time, a first liquid is injected into the submucosal layer 88 between the mucosal layer 89 and the muscular layer 87, and the mucosal layer 89 around the tumor 92 is cut out. A second liquid 98 is jetted and injected to the submucosal layer 88 between the mucosal layer 89 and the muscular layer 87, and the mucosal layer 89 and the muscular layer 87 are cut apart by an electric knife 71 in the submucosal layer 88 where the second liquid 98 was injected.SELECTED DRAWING: Figure 8【課題】安全かつ効率的に粘膜層の細胞組織を離断する方法を提供する。【解決手段】筋層８７上に粘膜下層８８、粘膜層８９が積層され、粘膜層８９内の腫瘍９２を離断する。このとき、粘膜層８９と筋層８７との間の粘膜下層８８に第１液体を注入し、腫瘍９２の周囲の粘膜層８９を切開し、粘膜層８９と筋層８７との間の粘膜下層８８に第２液体９８を噴射して注入し、第２液体９８が注入された場所の粘膜下層８８において粘膜層８９と筋層８７とを電気メス７１にて離断する。【選択図】図８
