PURPOSE: To improve the accuracy and safety of an electronic scale by providing a clock pulse generation part, a time difference detection part, a time difference counting means, a digital arithmetic part, etc.

CONSTITUTION: An electromagnetic force generating part 1 generate electromagnetic force which is balanced with the load W on a weighing pan 11 at a focus coil. The detection signal of the displacement of the coil is inputted to a pulse width modulator 4 through an amplifier 2 and a PID controller 3. This width modulator 4 generates a saw-tooth wave voltage in synchronism with clock pulses and this voltage is compared with the output voltage of the controller 3 to detect coincident time. Then, a rectangular wave pulse (HP) signal is outputted to control the opening and closing operation of an electronic switch 5, thereby supplying a current from a constant current source 6 to the focus coil. Then, an AND gate 7 passes clock pulses only while the HP signal is high and the lock pulses are counted by a counter 8. A time difference detector 9 detects the time difference between the rising time of the HP signal and a next clock pulse. its output is passed through an A/D conversion part 16 and weighted and added to the counted value of the counter 8 by a digital arithmetic part 12.