Abstract: When an image reading section reads an original color document a confidential portion of which is prepared in a specific color, an image processing apparatus receives authentication information such as a password from an operation section, and thereby compares the received authentication information with user information stored in a storage section so as to perform authentication. When the authentication is not completed, a controlling section issues an output stop instruction for the specific color to a color restricting section. The color restricting section deletes a specific color portion in the image data received from the image reading section. The image data the specific color portion of which is deleted is transmitted to an image forming section, and then printed out on recording paper.