PURPOSE: To obtain a time period for satisfactory disentanglement as long as possible during disentangling operation so as to greatly reduce unbalance upon dehydration by discharging water from a washing and dehydrating tank so that the level of water in the tank is steppedly lowered while an agitator is rotated normally and reversely by a rotating angle which is smaller than that during washing or rinsing operation, after the washing or rinsing operation but before dehydrating operation.

CONSTITUTION: During water discharging step, an agitator 11 is rotated normally and reversely by a rotating angle with a reversing time period which is shorter than that during washing or rinsing operation. Further, a discharge valve 17 is opened and closed repeatedly by an instruction from a control section 1, and accordingly, the level of water in a washing and dehydrating tank 8 is steppedly lowered during water discharging. During cloth disentangling operation with normal and reverse rotation having a small rotating angle, a time period during which the water level for satisfactory cloth disentanglement is held becomes longer than that in the case of leaving the discharge valve 17 in an open condition, since the water level is steppedly lowered, and thereby the cloth disentanglement can be enhanced further.