The invention relates to a catheter puncturing device for treating a patient during a medical treatment, said device structurally simplifying the placement of a catheter and reducing the number of required individual components of a catheter puncturing device. This is achieved by a catheter puncturing device according to the invention, said device being a closed single-piece system in which all the components required for the puncturing process are combined and provided in a housing. At the same time, the device allows the catheter to be released from the catheter puncturing device and to be uncovered using a handle after the catheter has been successfully introduced into the punctured vessel.