An image forming apparatus includes an image forming mechanism and an image fixing mechanism which includes a fixing member, a capacitor, a charger, a first heater, a second heater, a sensor, and a controller. The charger charges the capacitor with a first electric power. The first heater heats-the fixing member with the first electric power from the capacitor. The second heater heats the fixing member with a second electric power. The sensor detects a temperature of the fixing member. The controller controls the second electric power to control the second heater, determines whether the temperature is needed to be increased based on the temperature, and starts supplying the first electric power to the first heater from the capacitor when the second electric power is of a greatest value and when the temperature is needed to be increased.