Improvement in heat exchange efficiency can be promoted, a heat exchange can be efficiently performed, a space can be saved, and drying time can be shortened. A washing and drying machine includes a drum configured to accommodate clothes, a motor configured to drive the drum, a tub configured to accommodate the drum and store washing water, and a circulation flow path configured to circulate drying air into and out of the drum. A circulation duct constituting a part of the circulation flow path is connected to a converging portion configured to converge drying air. A dehumidifier is installed in one or more duct systems of the circulation duct. The washing and drying machine further includes a controller configured to control the dehumidifier and two duct cleaning pipes installed in branch ducts and configured to supply water to the dehumidifier.