The inventive system for withdrawing body fluid contains a driving unit (100, 100') comprising a pusher (10, 110) which is moved out of a rest position, into a piercing position in order to carry out the piercing process; and a piercing unit (20, 120, 120') containing a lancet (30, 130, 130') with a needle. Said needle is located inside the piercing unit when the pusher is in the rest position. When the pusher is moved into the piercing position, the needle is displaced by the same in such a way that said needle at least partially exits through an outlet opening (41, 41') in the piercing unit. The pusher and the lancet are interconnected with a form fit in order to carry out the piercing process. The invention also relates to a method for temporarily moving a needle out of a device for withdrawing body fluid, and to a piercing unit for mounting on a driving unit.