Septum resection method and endoscopic treatment device

An endoscopic treatment device, comprising:

• a sheath having a distal end portion and a proximal end portion;
• a first wire inserted through the sheath, the first wire being configured to protrude from the distal end portion of the sheath and the first wire being configured to cut tissue by being applied with current;
• a second wire inserted through the sheath, the second wire being configured to protrude from the distal end portion of the sheath and the second wire being configured to cut tissue by being applied with current;
• an insulative member configured to connect distal ends of the first wire and the second wire;
• a first insulative tube configured to cover the first wire protruding from the sheath, the first insulative tube being configured to move with respect to the first wire;
• and
• a second insulative tube configured to cover the second wire protruding from the sheath, the second insulative tube being configured to move with respect to the second wire,
• wherein the endoscopic treatment device is configured to switch between a first state in which the second wire protruding from the sheath is covered by the second insulative tube and a second state in which the first wire protruding from the sheath is covered by the first insulative tube.