In an operating unit constituting a stent delivery system, a protector for preventing an inner tube body from deforming is provided between a rack member and a containing groove guiding the rack member (so as to be movable. The protector, for example is a bellows shaped cylinder so as to be freely extendable and covers an outer circumferential side of the inner tube body. At the time of releasing a stent, the protector is compressed due to the movement of the rack member toward the proximal side and the inner tube body is prevented from deforming due to the protector, because an inner circumferential surface of the protector comes into contact with the inner tube body.
