Abstract: A cooking apparatus includes a cooking cavity to accommodate food to be cooked therein and a rotating unit to rotate while supporting the food. The rotating unit is installed within the cooking cavity to rotate by at least one roller which is in rolling contact with a bottom surface of the cooking cavity. A weight sensor is installed at a portion of the cooking cavity on a movement path of the roller to be temporarily pressurized by the roller when the rotating unit rotates. The weight sensor generates a load output signal according to a pressurized degree when the weight sensor is pressured by the roller, and generates a no-load output signal when the weight sensor is not pressurized by the roller. A control unit calculates a difference between the load output signal and the no-load output signal, and converts the difference to a weight of the food.