A heating apparatus of a washing machine and a washing method thereof. The heating apparatus includes a circulation channel installed outside a tub for connecting one side of the tub to the other side of the tub, and an orifice, water drop supply device for supplying water, an air blower for circulating the water, and a heater, which are sequentially installed in the circulation channel. The heating apparatus supplies steam or hot wind to the tub in a washing or rinsing operation, thereby improving the washing capacity of the washing machine, minimizing the time taken to perform the washing or rinsing operation and an energy consumption rate, and allows the washing machine to perform a drying operation using hot wind without any additional element, thereby diversifying its functions and minimizing production costs.