The present invention relates to a method for washing a washing tub (120) in a washing machine, and a washing machine having a washing tub washing course provided thereto for enabling washing tub (120) washing by the same, and more particularly, to a method for which makes effective washing tub washing, with a small amount of washing water consumption, a lower power consumption, and high washing effect; and a washing machine having the same applied thereto. A method for washing a tub (120) or a drum (130) in a washing machine having the tub (120), the drum (130) rotatably mounted in the tub (120), and a steam supply unit for supplying steam to the tub (120), includes a steam supply step for supplying steam to the tub by using the steam supply unit.