Washing machine

Provided is a washing machine that makes it possible to effectively exert a sterilizing effect onto all the inner wall face from a lower portion to an upper portion of a washing tank, to shorten a driving time required for washing the washing tank and also to reduce an amount of water to be used for the washing process. The washing machine is provided with a rotatable washing tank that has no hole in the tank wall, and is formed so that a diameter of the inner wall face becomes gradually greater toward an opening portion, as well as a water supply valve, a water supply pipe and an water supply inlet that serve as a water supply unit capable of supplying water having a sterilizing effect to the washing tank, and in this structure, silver ion-containing water, supplied to the washing tank by the water supply unit, is allowed to move and flow along the inner wall face of the washing tank by the centrifugal force derived from the rotation of the washing tank so as to sterilize the inner wall face of the washing tank.