Abstract: An insertion device including a handle, a flexible shaft elongated at least in part with a movable distal portion controllable by a user interface, and a driving system for transforming actuation from the user interface to movement of the distal portion. The driving system has a housing leak-tightly connected to the shaft from one side and from the opposite side the housing is provided with the first detachable leak-tight fastening means, whereas the handle is provided with the second detachable leak-tight fastening means. A method of preparation for reuse of an insertion device in which the shaft is subjected to the treatment of at least one agent wherein subjected to disinfection is shaft with the driving system, whereas the handle with the user interface is detached from the driving system for the disinfection time.