An image forming apparatus has a pad type fixing device in which a lubricant is interposed between a fixing belt for heating a sheet and a pad for holding the fixing belt, and includes: a controller that controls a heater of the fixing belt to maintain a fixing temperature to be set in accordance with printing modes, at a set temperature; an acquisitor that acquires torque of a motor for rotating the fixing belt as acquired torque for each of the set temperatures; a transition predictor that predicts transition of the torque of the motor for each of the set temperatures based on the acquired torque; and a point predictor that predicts a point at which at least two transition curves based on the predicted transition intersect each other as a torque rise point at which the torque of the motor starts rising due to a decrease in the lubricant.