A fixing device includes a rotational member configured to convey and heat a sheet-shaped recording medium, the rotational member including a first heating member and a second heating member provided in parallel to a rotational axis of the rotational member in an interior thereof, the first heating member including a first heat generation part, the second heating member including a second heat generation part and an auxiliary heat generation part adjacent to the second heat generation part, a common temperature sensor configured to sense a temperature of the first heating member and a temperature of the second heating member, and a control part configured to control a ratio of a rate of lighting of the first heating member and a rate of lighting of the second heating member based on the temperature of the first heating member and the temperature of the second heating member.