PURPOSE: To easily judge whether or not a sheet is tightly attracted to a surface of an electrostatic attracting drum.

CONSTITUTION: In a device provided with a drum 3 equipped with a positive and a negative electrodes embedded in a surface thereof for electrostatically attracting a sheet 2 to the surface, and a high voltage power source device for applying high voltage to the electrodes, an input current value to the high voltage power source device is detected and the detected input current value is compared with a preliminarily determined reference value to judge whether or not the sheet 2 is tightly stuck to a surface of the drum 3.