To provide a washing and drying machine capable of effectively utilizing the time of a washing step, shortening the time in a drying step and efficiently using energy generated in the washing step.

In the washing and drying machine including a water tub 2 for housing laundry, a heat radiation part 13 for radiating heat by compressing a refrigerant and a heat absorption part 14 for taking away the heat around the refrigerant by expanding the refrigerant, for heating washing water to be supplied to the water tub 2 in the heat radiation part 13 and cooling drying air discharged from the water tub 2 in the heat absorption part 14, the heat absorption part 14 stores cold air generated by taking away the heat around the refrigerant by the expanded refrigerant when the washing water is heated in the heat radiation part 13 in a washing step and a rinsing step.