A washing and drying machine comprises a rotating tub (3) with small holes made in its circumferential wall to receive laundry, a water tub (2) provided around the outer periphery of the rotating tub (3) to store water, an air circulating passage (12) for communication between the inside and outside of the water tub (2) for air circulation, a warm air generation unit (40) to make air in air circulating passage (12) warm, an overflow stream outlet (17) provided at the water tub (2) to drain water when the water level of the water tub (2) is higher than a predetermined level. The washing and drying machine is characterized by an air stopping unit (41) provided in a water drain passage (21) communicating with the overflow stream outlet (17) so that water can be supplied and an sir flow can be stopped.