ELECTRICAL POTENTIAL MEASUREMENT DEVICE

PROBLEM TO BE SOLVED: To provide a contactless electrical potential measurement device with improved measurement sensitivity.SOLUTION: An electrical potential measurement device 10A, which contactlessly measures electrical potential of a charged object using a sensor 60, includes: first and second shutters 40A and 50A having shutter sections 44 and 54 provided with openings 45 and 55, respectively and flat spring sections 41 and 51, respectively; magnets 80 mounted on the flat spring sections 41 and 51 of the first and second shutters 40A and 50A; a yoke 31 provided with coils 33 which apply an alternating magnetic field to the magnets 80 on each of the first and second shutters 40A and 50A to move the shutter sections 44 and 54 back and forth via the flat spring sections 41 and 51; and natural frequency adjusting means 100 for adjusting the natural frequency of at least one of a first shutter system 400A comprising the first shutter 40A and the magnets 80, and a second shutter system 500A comprising the second shutter 50A and the magnets 80.