An image forming apparatus includes a first authentication portion performing a first authentication process on a user, a second authentication portion that performs a second authentication process on the user successfully authenticated by the first authentication portion, and thereby determines whether or not the user is permitted to log onto the apparatus, and a cooperative setting portion performing setting therethrough, on a user-by-user basis, whether or not the first authentication process and the second authentication process are performed in combination with each other. If the user for whom setting is performed such that the first authentication process and the second authentication process are performed in combination with each other is successfully authenticated by the first authentication portion, then the second authentication portion determines that the user is to be permitted to log onto the apparatus based on the associated information and ends the second authentication process.