Abstract: The invention relates to an apparatus for the electrochemical processing of workpieces. The apparatus comprises a processing electrode (2) adjustable in relation to the workpiece (1) and a supply unit (3) for the electric working value supplied to the workpiece (1). The store (8) comprises in the form of digital measured values the course in time during processing of the working value detected by a measuring system (5). In a comparison stage (7) the stored course in time of the working value, serving as a required value, is compared with the course delivered by the measuring system (5) (actual value), and a control signal is delivered to the supply unit (3) when a given difference between the required and actual values is exceeded.