An insertion device for an infusion set includes an advancement unit or a sliding element for moving the infusion set along a central axis from a proximal position into a distal position, a retaining element for retaining the infusion set that includes a guide element, a base part for accommodating the retaining element that includes a mating guide element and a contact surface for placing the insertion device on an application point of a patient's body, and a head part arranged rotatably about a central axis in relation to the base part. Upon relative rotation between the head part and the base part in one direction, the guide element of the retaining element can be guided with the mating guide element provided on the base part such that the retaining element is movable along the central axis relative to the base part from the distal position into the proximal position.
