A delivery device is provided for delivering a stent device. The stent device (2) is radially expandable from a radially reduced, delivery configuration to a radially expanded, deployment configuration. A restraining sheath (4) is mounted coaxially over the stent device for maintaining the stent device in the delivery configuration. The restraining sheath has a line of weakness (6) extending axially therealong. A pull member is provided, which is to be pulled so as to split the restraining sheath at the line of weakness and withdraw the restraining sheath from over the stent device. The pull member and the line of weakness are located on opposing sides of the restraining sheath. The pull member (5) is wrapped around a distal end of the restraining sheath. The wrap around portion may be formed by a hook of a metal pull member. The wrap around portion may be formed by an open loop of polymer thread. Both ends of the open loop may extend proximally from the restraining sheath and the stent device with one of the ends being fixed to the delivery device and the other being moveable to provide a pull end.
