The syringe pump comprises a receiving position for a syringe. The piston plate of the syringe is moved by a drive head which is fastened to a drive rod. For locking the piston rod prior to fixing the piston plate in the drive head, a braking element is provided on a syringe holding head. The syringe holding head further serves for determining the respective syringe size. After placing the syringe holding head against a syringe cylinder, the brake element is actuated to temporarily engage the piston rod and fix it relatively to the syringe cylinder.