In an image forming apparatus, a first abnormality detection portion detects an abnormality in a fixing portion based on a change rate of a temperature detected by a temperature detecting portion and a first reference change rate that is set in advance. A first temperature control portion performs a temperature control of a heat source by a first feedback control method based on the temperature detected by the temperature detecting portion. A second temperature control portion performs a temperature control of the heat source by a second feedback control method based on the temperature detected by the temperature detecting portion, the second feedback control method being smaller in temperature change rate than the first feedback control method. A detection prohibiting portion prohibits the abnormality detection by the first abnormality detection portion during the temperature control performed by the second temperature control portion.