A method includes providing an indwelling tool (15 65 75 95) having a magnetic body (20 61 70 90) at the inside of a luminal organ (W1) by inserting the tool into a working channel (44) inserted from a natural opening of a living body to the luminal organ, in a manner such that an axis along a length of the magnetic body is arranged substantially parallel to a length direction of the working channel disposing the tool in a vicinity of a diseased part of the luminal organ applying a magnetic field to the magnetic body by using a magnetic field generating device (30 80) provided at the outside of the luminal organ, so as to attract the magnetic body and make a side face of the magnetic body along the axis thereof push against a tissue in the vicinity of the diseased part and lifting a tissue around a position of the tool, which includes the diseased part, by applying a magnetic force to the magnetic body by using the magnetic field generating device.
