An image forming device. A direct voltage power supply is independently provided for each charging device for each color, and an alternating voltage power supply is commonly provided to the charging device for each color. A current detecting section detects current which flows between each image carrying body and each charging device. A control device judges that the image carrying body is damaged when a detected current value is not less than a preliminarily set specified value when a direct voltage is sequentially independently applied to the charging device for each color when leakage of charging voltage is generated.