<p>A control unit for controlling a water-supply unit, a heating unit and a washing unit on the basis of the sensed temperature by a temperature sensing unit to execute at least a thermal capability estimating step, a washing step, a heat/rinse step and a drying step detects and controls the capacity of an object to be washed by comparing the temperature rise rate of wash water in the thermal capability estimating step with the temperature rise rate of wash water in the washing step. This makes it possible to determine the capacity of dishes obtained by minimizing the effect of the variations in the number of watts of a heater or the power supply voltage situation under the environment in which a dishwasher is installed.</p>
