An OCT catheter includes an interior member including a torque wire and an optical fiber, the torque wire transmitting rotation from a proximal end toward a distal end, the optical fiber being provided in a hollow portion of the torque wire and transmitting light. The OCT catheter further includes an outer housing 30 covering the interior member. The outer housing includes inside a pair of stepped portions that face each other in a lengthwise direction of the torque wire. The torque wire includes a torque-wire body and a flange provided on the torque-wire body. The flange is provided between the pair of stepped portions. A coil spring is provided between one of the pair of stepped portions and the flange. The flange is pressed toward the other of the pair of stepped portions by the coil spring.
