An image forming apparatus includes a main CPU 70. During an unused period in which the image forming apparatus is not used, the main CPU 70 detects, based on the output of a first operation detection sensor, the presence of a first operation, which is an operation that causes a concern that consumable items or the like may be stolen. When the main CPU 70 detects the first operation, theft alert audio which indicates that there is a concern that consumable items or the like may be stolen is output from a speaker. Also, the main CPU 70 transmits an email to a pre-registered destination which includes a theft alert message, which indicates that there is a concern that consumable items or the like may be stolen.