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 one 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 the at least one 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 ; characterized in that - a locking mechanism is provided and in operative connection to the thumbwheel , which locking mechanism causes, upon reaching at least one defined angle (α) of rotation of the thumbwheel , a locking state of the rotational mobility of the thumbwheel and thereby of the proximal displaceability of the outer sheath ; and that - an unlocking mechanism is provided and in operative connection to the locking mechanism , by means of which unlocking mechanism the locking state is reversible, - characterized in that the locking mechanism includes a rotatably mounted driving gear which is driven by the thumbwheel , a rotatably mounted driven gear which is driven by the driving gear , and a movably mounted locking member on which the driven gear comes into abutment upon reaching the at least one defined angle (α) of rotation of the thumbwheel , thereby producing the locking state, wherein the locking member is displaceable relative to the driven gear by means of the unlocking mechanism for reversing the locking state. - 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 one 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 the at least one 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 ; - a locking mechanism is provided and in operative connection to the thumbwheel , which locking mechanism causes, upon reaching at least one defined angle (α) of rotation of the thumbwheel , a locking state of the rotational mobility of the thumbwheel and thereby of the proximal displaceability of the outer sheath ; and that - an unlocking mechanism is provided and in operative connection to the locking mechanism , by means of which unlocking mechanism the locking state is reversible, - characterized in that the locking mechanism includes a rotatably mounted driving gear which is driven by the thumbwheel , a rotatably mounted driven gear which is driven by the driving gear , and a movably mounted locking member on which the driven gear comes into abutment upon reaching the at least one defined angle (α) of rotation of the thumbwheel , thereby producing the locking state, wherein the locking member is displaceable relative to the driven gear by means of the unlocking mechanism for reversing the locking state. <EOS>