Method of controlling with heightened accuracy a processing machine driven at different operating speeds, the processing machine having machine tool means displaceable over a given full range and a machine part moving in synchronism with a cycle of the process that has been instituted in advance through a precontrolled time period dependent upon the operating speed and which includes a control commencement build-up time and a time period for the full-range displacement of the machine tool means, and, at an initial setting of the moving machine part, within a given tolerance range permitting start-up of said processing cycle, which comprises interposing a blocking time period between the control commencement build-up time period and the full-range displacement time period, the blocking time period always ending at an instant at which the moving machine part is at the same position in the displacement range thereof, blocking the full-range displacement of the machine tool means until the end of the blocking time period, and advancing the start of the control commencement build-up time period in accordance with the blocking time period.