An image forming apparatus has a fixing unit for fixing a toner image formed on a recording material, and a heater, for heating the fixing unit, made of a carbon-based material. In order to detect and expect the life of the heating unit with good accuracy, the image forming apparatus further has a current measuring device for measuring a current passing through the heating unit and a notification device for providing notification of information on a life of the heating unit depending on an output of the current measuring device.