To provide an OCT catheter configured such that the movement of an interior member in the front-rear direction in an outer housing is suppressed. An OCT catheter includes an interior member 20 including a torque wire 21 and an optical fiber 25, the torque wire 21 transmitting rotation from a proximal end toward a distal end, the optical fiber 25 being provided in a hollow portion of the torque wire 21 and transmitting light. The OCT catheter further includes an outer housing 30 covering the interior member 20. The outer housing 30 includes a pair of stepped portions (a wall portion 36a and a stepped portion 33a) that face each other in a lengthwise direction of the torque wire 21. The torque wire 21 includes a torque-wire body 22 and a flange portion 23 provided on the torque-wire body 22. The flange portion 23 is provided between the pair of stepped portions. A coil spring 48 is provided between one of the pair of stepped portions and the flange portion 23. The flange portion 23 is pressed toward the other of the pair of stepped portions by the coil spring 48.
