The present invention is directed to a stylet device to allow easy advancement of a tube through complex passages of body cavities. The stylet 210 is structured such that its distal end bends actively according to the operation of the tension-conferring device 220. This makes it possible for guidance member 120 of tube 100 in which stylet 210 has been inserted to bend actively. By insertion into a body cavity the tube 100 that uses stylet device 200 that is able to bend actively in this way, it is possible to align the distal end of tube 100 with the direction of the passage, and to pass tube 100 easily through even complex passages of the body cavity.
