The utility model particularly provides an accurate machinery return-to-zero device for a digital quantity scanning probe applied to precision measurement equipment, which is characterized in that the fixed end of a flat spring mechanism is connected with a lever base. The lever base is connected with a lever through a flat spring. The lever can be flexibly rotated and has no gap and no idle stroke during the rotation process. Fulcrum screws arranged on the lever base are used for adjusting the measurement stroke and protecting the entire probe mechanism. The moving end of the flat spring mechanism is connected with a force measurement bearer. Left and right fulcrum screws are arranged on the force measurement bearer. The fixed end of the flat spring mechanism is connected with a spring bracket and the two ends of the spring bracket are connected with spring pressing blocks for adjusting the amplitudes of the measuring forces of force measurement springs, adjusting the gradients of two springs, and adjusting the return-to-zero speed of the probe. The fixed end of the flat spring mechanism is connected with a grating holder and a grating sensor is fixedly arranged on the grating holder. The moving end of the flat spring mechanism is connected with a grating ruler holder and a grating ruler is attached onto the grating ruler holder. The accurate machinery return-to-zero device is accurate in machinery return-to-zero effect, and the left and right measuring forces of the device are equal. Therefore, the easy drifting phenomenon of the electrical null position is avoided. Meanwhile, measurement results in the left and right directions are ensured to be consistent.