The present invention relates to the technical filed of washing machine, and discloses a filter device, a washing machine, and a control method. The filter device, comprising: a filter chamber having a water inlet and a filtered water outlet, and a sealing support part formed by the outer circumference of the filtered water outlet being extended toward the outside the filter chamber; a filter mechanism, being rotatably arranged in the filter chamber, wherein an end of the filter mechanism is a water outlet joint inserted in the sealing support part, and the water outlet joint is rotatably and hermetically connected with the sealing support part; a first bearing, being sleeved on the water outlet joint; and a first sealing member, being disposed on the side of the first bearing facing the inside of the filter chamber, for sealing the gap between the water outlet joint and the sealing support part. In the present invention, the first bearing supports the water outlet j oint, so that the filter mechanism is more stably mounted in the filter chamber and rotate more smoothly. In addition, the first sealing member can prevent water in the first bearing from making contact with water in the filter chamber, thereby ensuring the action effect of the first bearing.