A washing machine with a drying function can include a tub, a drum inside the tub and including: a cylindrical body having a rear end opening, and a drum back coupled to the cylindrical body to be over the rear end opening and including: a plurality of recess portions, a plurality of openings between adjacent recess portions and a plurality of porous plates coupled to the plurality of openings, a motor to provide a rotational force to the drum, a flange shaft between the drum and the motor to transmit the rotational force of the motor to the drum and including: a hub, and a plurality of flange portions extending radially from the hub, a drying duct configured to supply heated air into the tub, and an exhaust duct configured to return the heated air from the tub through the plurality of porous plates to the drying duct.