In a fixing apparatus, a first detection portion detects a temperature of an atmosphere (a first detected temperature) attained by heat conduction from a heating rotating member for fixing a toner image on a sheet of paper by heating, at a position above the heating rotating member. A second detection portion detects a quantity of infrared rays radiated from the heating rotating member, to thereby detect a temperature at a position below the heating rotating member. A heating portion heats the heating rotating member. A control portion controls heating by the heating portion based on a second detected temperature corresponding to the quantity of infrared rays and the first detected temperature.