A fixing device comprises a cylindrical sheet heating body for heating a sheet; a heat generation section which includes a center heat element that generates heat in a central area, a first heat element that generates heat in a first area containing an end in the length direction, and a second heat element that generates heat in a second area between the central area and the first area; a center temperature measurement section which measures a temperature of a portion of the sheet heating body; a both-end temperature measurement section which measures a temperature of the sheet heating body at a destination by moving in the length direction; and a power controller configured to control electric power to be supplied to the center heat element, to the first heat element, and to the second heat element according to the center temperature measurement section and the both-end temperature measurement section.