PROBLEM TO BE SOLVED: To provide a surface potential measuring device which can effectively measure the surface potential of a measurement object existing in a vacuum. ! SOLUTION: A surface potential measuring device includes a glass insulating member 3 which is provided on a vacuum partition TC1 and which is dielectrically polarized by an electric field; a surface potentiometer 4 having a sensor part 41 which faces measurement objects W, 13 existing inside the vacuum partition TC1 through the insulating member 3; and cancel means for eliminating the electrification of a surface of the insulating member 3 when the surface potential of the measurement object W is measured by the sensor part 41. ! COPYRIGHT: (C)2014,JPO&INPIT
