Stent delivery system, comprising: - a handling device having a housing, a thumbwheel mounted in the housing to be rotatable, and a winding spool rotating together with the thumbwheel; - a catheter arrangement having an inner shaft, with a proximal end of the inner shaft fixed on the housing, an outer sheath disposed coaxially to the inner shaft, and having at least a first stent which is received radially between the inner shaft and the outer sheath; - a flexible pull member which, with one end, engages on a proximal end of the outer sheath and, with the other end, is held on the winding spool to be windable; - wherein, for release of at least the first stent, the outer sheath is displaceable relative to the inner shaft in the proximal direction by means of winding the flexible pull member on the winding spool; - wherein the winding spool has different winding diameters (W1, W2) on which the flexible pull member engages and is windable in different displacement positions (P1, P2, P3) of the outer sheath, whereby different transmission ratios result between the rotation movement of the thumbwheel and the proximal displacing movement of the outer sheath; - wherein the winding spool has at least a first winding diameter formed on a first axial section on which the flexible pull member engages during an initial displacement move of the outer sheath between a first displacement position and a second displacement position, and a second winding diameter formed on a second axial section on which the flexible pull member engages during a subsequent displacement move of the outer sheath between the second displacement position and a third displacement position; - wherein the winding spool has a helical circumferential groove, with the groove bottom thereof providing the first winding diameter, wherein the winding spool has a cylindrical section, with the outer diameter thereof providing the second winding diameter, and wherein the first winding diameter is larger than the second winding diameter; - characterized in that a first radial shoulder is disposed in axial direction between the first axial section and the second axial section, the first radial shoulder forming a step between the first winding diameter and the second winding diameter, thereby causing, during winding of the flexible pull member, a quasi-abrupt and non-continuous transition of the transmission ratio. - a handling device having a housing, a thumbwheel mounted in the housing to be rotatable, and a winding spool rotating together with the thumbwheel; - a catheter arrangement having an inner shaft, with a proximal end of the inner shaft fixed on the housing, an outer sheath disposed coaxially to the inner shaft, and having at least a first stent which is received radially between the inner shaft and the outer sheath; - a flexible pull member which, with one end, engages on a proximal end of the outer sheath and, with the other end, is held on the winding spool to be windable; - wherein, for release of at least the first stent, the outer sheath is displaceable relative to the inner shaft in the proximal direction by means of winding the flexible pull member on the winding spool; - wherein the winding spool has different winding diameters (W1, W2) on which the flexible pull member engages and is windable in different displacement positions (P1, P2, P3) of the outer sheath, whereby different transmission ratios result between the rotation movement of the thumbwheel and the proximal displacing movement of the outer sheath; - wherein the winding spool has at least a first winding diameter formed on a first axial section on which the flexible pull member engages during an initial displacement move of the outer sheath between a first displacement position and a second displacement position, and a second winding diameter formed on a second axial section on which the flexible pull member engages during a subsequent displacement move of the outer sheath between the second displacement position and a third displacement position; - wherein the winding spool has a helical circumferential groove, with the groove bottom thereof providing the first winding diameter, wherein the winding spool has a cylindrical section, with the outer diameter thereof providing the second winding diameter, and wherein the first winding diameter is larger than the second winding diameter; - characterized in that a first radial shoulder is disposed in axial direction between the first axial section and the second axial section, the first radial shoulder forming a step between the first winding diameter and the second winding diameter, thereby causing, during winding of the flexible pull member, a quasi-abrupt and non-continuous transition of the transmission ratio.