To provide a washing machine capable of supplying a washing tank with metal ion water of enough density of metal ions to suppress propagation of bacteria, especially molds, in the cleaning tank and performing tank cleaning which does not stick excessive metal ions to laundry.

A washing and drying machine 100 includes a water tank 2 for housing laundry, a metal ion water supply part 6 for generating metal ionic water to supply the ion water to the water tank 2; and a laundry presence detection part 9 for detecting whether or not there is laundry in the water tank 2. When the laundry presence detection part 9 detects that there is no laundry in the water tank 2, the metal ion water supply part 6 generates the metal ion water to supply the metal ion water to the water tank 2.