A neutralizing device for an electric-insulating sheet comprising at least two neutralizing units provided on the moving route of an electric-insulating sheet at intervals in the moving direction of the sheet, each neutralizing unit having a first electrode unit disposed on the first surface side of the sheet and a second electrode unit disposed on the second surface side of the sheet, the first electrode unit having a first ion generating electrode, the second electrode unit having a second ion generating electrode disposed facing the first ion generating electrode, wherein, in each neutralizing unit, the first ion generating electrode and the second ion generating electrode are so related as to be given a dc inter-ion-generating-electrode potential difference, and, when a total number of the neutralizing units is n (n: integer of at least two), the inter-ion-generating-electrode potential difference in at least n/4 (fractional portion rounded up) neutralizing units out of n neutralizing units and the inter-ion-generating-electrode potential difference in the other neutralizing units are in mutually-reverse-polarity potential difference relation.