PROBLEM TO BE SOLVED: To grasp the position of an ultrasonic vibrator in X-ray fluoroscopy without impairing the performance of an ultrasonic catheter. SOLUTION: This ultrasonic catheter 1 is provided with a driving shaft 10 housed in a catheter sheath 2 for transmitting the mechanical driving force from this side of the catheter sheath 2 to the top side and the ultrasonic vibrator 13 connected to the tip side of the driving shaft 10. An X-ray contrast applying means 12 is provided at least in a part of the driving shaft 10.
