Abstract: A puncture device with a flexible catheter tube for connecting to a medical infusion line, wherein the device includes a catheter connecting piece or hub attachable at the puncture site on the skin surface of a patient, wherein the catheter hub has a connector for connecting the infusion line and an outlet for the flexible catheter tube; and a needle holder having a puncture needle (stylet), wherein the flexible catheter tube is arranged in the interior of the catheter hub and extends out of the outlet with an output end. The end of the flexible catheter tube opposing the output end is located in the interior of the catheter hub in the area of the connector and is separated from the surrounding area by a septum, wherein the needle holder securely fastens the puncture needle insertable into a passage channel of the catheter tube at the end opposing the pointed or sharp puncture tip.