The image forming apparatus includes a fixing apparatus including a heater that includes at least two heat generation members, the fixing unit configured to fix an unfixed toner image formed on a sheet by an image forming unit, a heat generation member switching device configured to switch a power supply path so that electric power can be supplied to one of the heat generation members, a CPU configured to control switching the power supply path by the heat generation member switching device based on a number of shorter width sheets in a longitudinal direction continuously printed in a case where a plurality of mixed sheets including longer width sheets and the shorter width sheets.