Abstract: The sampling device for chemical, in particular biochemical process technics, consists of a sterilizable container in which a magnetic stirring system is accommodated whose agitator beam may be adjusted in height also in operation. Fluid flows through a tangential inlet near the bottom to be discharged through an outlet provided in the upper end wall. Beneath the filter membrane there is an extremely small dead space through which the filtrate gets to the filtrate outlet. The lower end of the agitator arm is designed as a pointed flow break-away edge which, in case of rotation, generates an alternating pressure field migrating over the membrane. The device is particularly characterized by short response times and by a long service life due to the fact that without a substantial shearing, the filter membrane is kept free from deposits.