PURPOSE: To satisfy a cleaning performance, etc., by preventing the state of an agitation stream being too strong for a cloth quantity and performing a wash through an appropriate stream and by performing a wash through the appropriate stream, even when a cloth is difficult to move by the intertwinement of the washing, etc.

CONSTITUTION: Water is supplied to a tank 2 until it reaches a predetermined level, and a cloth load is determined by a cloth load-determining means 17. After that, water is supplied up to a level corresponding to the cloth load and the apparatus is operated at the level for a predetermined agitation period. Then, the state of cloth is determined by the damped state from a voltage detection means 14 within the OFF period of a motor 5 in agitation so that the agitation period is controlled, and according to the controlled agitation period, the state of the cloth is again determined by the damped state from said voltage detection means 14 within the OFF period of the motor 5 in agitation so that the agitation period is controlled repeatedly and continuously.