A washing machine that includes an integrated tub/drum that holds water, accommodates laundry, and rotates; a hollow rotary shaft coupled to and passing through one surface of the integrated tub/drum; a water supply pipe and a water drain pipe in the integrated tub/drum and through a passage or opening in the hollow rotary shaft; a nozzle that extends upward from an end of the water supply pipe that is in the integrated tub/drum; and a water drain that extends downward from an end of the water drain pipe that is in the integrated tub/drum.