The invention relates to a catheter stylet for stiffening a catheter during the placing process, wherein the stylet comprises an accommodating lumen for at least one fluid-guiding line of the catheter. It also relates to a catheter stylet catheter system, comprising such a stylet and comprising a catheter which comprises a fluid-guiding line, and to a method for stiffening a catheter during the placing process, wherein a stylet which comprises an accommodating lumen is arranged around at least one fluid-guiding line of the catheter.