An image forming apparatus includes an image forming unit for forming a toner image on a sheet of paper; a fixing unit for fixing the toner image formed on the sheet of paper by heat; a power control unit for, when power to be supplied to the fixing unit is increased, determining an amount of increase of the power; and a current limiting unit for determining whether current consumption of the image forming apparatus exceeds an upper limit value in response to an increase of the amount of increase determined by the power control unit and, if it is determined that the current consumption exceeds the upper limit value, decreasing the amount of increase of the power determined by the power control unit.