In an image forming device, output is prohibited by an output control unit if specific image data is detected in image data obtained by reading an original document. The current data is acquired when the output control unit prohibits output, and the password is created in accordance with the current data. The image data which is prohibited from being output by the output control unit is transmitted to an administrator, and then if output permission is obtained by the administrator, output permitted data is generated as an image in which a password created by the password creating unit is embedded in such a manner that a user can not identify the password, and is output by the output unit. The output permitted image outputted by the output unit is read by the reading unit, and then the embedded password data is extracted by the extraction unit. If it is determined that the password extracted by the extraction unit and the password created by the password creating unit correspond to each other, the prohibition on the output will be lifted.