MEDICAL DEVICE

PROBLEM TO BE SOLVED: To provide a medical device capable of performing effective image diagnosis by preventing abnormal vibration of a drive shaft within an inner tube when the drive shaft is pulled back.SOLUTION: The medical device 1 includes: a sheath 2 to be inserted into a living lumen; the drive shaft 42 inserted into the sheath 2 for transmitting mechanical drive force; a detecting means 41 fixed to the distal end on the sheath side of the drive shaft 42; a hub 31 for moving the drive shaft 42 in the axial direction of the sheath by moving while holding the drive shaft 42; an outer tube 33 fixed on the hub side of the sheath 2 or on the sheath side of the hub 31; the inner tube 312 which relatively moves to the outer tube 33 inside the outer tube 33 according to the movement of the hub 31; and a protection tube which contracts in the axial direction of the drive shaft 42 inside the inner tube 312 according to the movement of the inner tube 312 to let the drive shaft 42 pass through the tube.