To easily take out a wash after dewatering finishes by successively performing respective processes such as washing, rinsing and spinning by driving a rotary drum to rotate in the almost horizontal direction by a motor, and performing a cloth unfastening process to rotate the rotary drum for a prescribed time after the final dewatering process.

The laundry is put in a rotary drum 1, and when operation is started, first of all, after the rotary drum 1 is driven at a rotating speed N1 by a first motor 18, it is raised up to a rotating speed N3(>N1) by a second motor 19, and next, current-carrying of the second motor 19 is cut off, and a quantity of a wash is detected from a rotating speed at inertial rotation time of the rotary drum 1 at that time. Next, a feed valve 16 is opened, and water is supplied by a prescribed quantity, and washing is started. After the washing finishes, the water is drained, and a rinsing process is performed, and dewatering is performed. After the final dewatering process, the rotary drum 1 is reversed at the rotating speed N1 at a prescribed time interval, and the laundry sticking to the rotary drum 1 is dropped, and the laundry can be easily taken out thereafter.