WASHING MACHINE

PROBLEM TO BE SOLVED: To provide a washing machine capable of shortening time needed for washing without making a water tub dirty.SOLUTION: A washing machine 100 includes: a water tub 2; a washing tub 3; a water supply channel 12; a water drain channel 17; a filter 8; a cleaning channel 13; a drain valve 50; a water drain channel 16; a drain valve 55; and valves 51, 52 and 53. The cleaning channel 13 is connected to a part between the filter 8 in the water supply channel 12 and the water tub 2, and an introduction channel 11. The water drain channel 16 is connected to a part between the filter 8 in the water supply channel 12 and the valve 51, and the water drain channel 17. The water drain channel 16 circulates water that is supplied from the cleaning channel 13 to the filter 8 and that washes the filter 8. The drain valve 50 is arranged between a connection part 17b where the water drain channel 17 and the water drain channel 16 are connected, and the water tub 2. The drain valve 55 is arranged in the water drain channel 16.