A housing (54) constituting a stent delivery system (10) is provided with a curved wall (70) facing a rotary roller (60), and is also provided with a support body (104) in sliding contact with an outer circumferential surface of a main body (92) in the rotary roller (60). A resilient member (106) composed of a coil spring is provided between the support body (104) and the curved wall (70). In a case where, for any reason, it becomes difficult to move a rack member (56) in the axial direction and an operator forcibly rotates the rotary roller (60), a load of not less than a predetermined value is applied to the rotary roller (60) and the rotary roller (60) moves downward while the support body (104) is being pushed down, and a non-meshed state is adopted in which meshing between the rack member (56) and the rotary roller (60) is released. Movement of the rack member (56) in the axial direction is thereby avoided, there being no transmission of the rotating force of the rotary roller (60) to the rack member (56).
