An image forming apparatus includes: an imaging device that forms a toner image based on image data and transfers the toner image to a recording medium; a fixing device including a pair of rotatable members that defines a contact pressing portion that allows the recording medium with the toner image to pass through, and heats and presses the recording medium with the toner image; a surface potential measuring device that measures a surface potential of at least one of the pair of rotatable members; and a controller that performs control to give an alert notification that at least one of the pair of rotatable members which contacts with the toner image to be fixed should be replaced, when a result of the surface potential measured by the surface potential measuring device has exceeded a predetermined value.