An injection device having a safeguard for preventing a filling or adjusting motion of the injection device when a prescribed dispensing motion has been performed, the injection device including an adjusting element and/or a filling element, a blocking mechanism including a first blocking element and a second blocking element, the blocking mechanism allowing a motion of the adjusting and/or filling element in a release position and preventing the motion in a blocking position, and a piston rod including a block trigger element that can bring one of the blocking elements into interaction with the other blocking element thereby creating a blocking position at a prescribed insertion position to cause a blocking of at least one of the adjusting element and/or the filling element.