A washing machine comprising: a washing tub ; and a water transmission device configured to discharge water of the washing tub , the water transmission device including: a filter case disposed under the washing tub, the filter case accommodating a filter, and the filter case accepting the water from the washing tub; a pump case connected to the filter case, the pump case accommodating an impeller , the impeller configured to suction the water in the filter case and discharge; a motor configured to rotate the impeller; a suction hole communicating a side portion of the pump case facing a center of the impeller with a side portion of the filter case; a water discharge pipeline formed under the pump case ; and an outlet opened downward from a lowest end inside the pump case, the outlet communicating with the water discharge pipeline , wherein an upper region inside the filter! case communicates with an interior of the pump case through the suction hole , characterized in that the washing machine further comprises one or more communicating paths provided under the suction hole , the one or more communicating paths communicating a lower region inside the filter case with the outlet . a washing tub ; and a water transmission device configured to discharge water of the washing tub , the water transmission device including: a filter case disposed under the washing tub, the filter case accommodating a filter, and the filter case accepting the water from the washing tub; a pump case connected to the filter case, the pump case accommodating an impeller , the impeller configured to suction the water in the filter case and discharge; a motor configured to rotate the impeller; a suction hole communicating a side portion of the pump case facing a center of the impeller with a side portion of the filter case; a water discharge pipeline formed under the pump case ; and an outlet opened downward from a lowest end inside the pump case, the outlet communicating with the water discharge pipeline , wherein an upper region inside the filter! case communicates with an interior of the pump case through the suction hole , characterized in that the washing machine further comprises one or more communicating paths provided under the suction hole , the one or more communicating paths communicating a lower region inside the filter case with the outlet . a filter case disposed under the washing tub, the filter case accommodating a filter, and the filter case accepting the water from the washing tub; a pump case connected to the filter case, the pump case accommodating an impeller , the impeller configured to suction the water in the filter case and discharge; a motor configured to rotate the impeller; a suction hole communicating a side portion of the pump case facing a center of the impeller with a side portion of the filter case; a water discharge pipeline formed under the pump case ; and an outlet opened downward from a lowest end inside the pump case, the outlet communicating with the water discharge pipeline , wherein an upper region inside the filter! case communicates with an interior of the pump case through the suction hole , characterized in that the washing machine further comprises one or more communicating paths provided under the suction hole , the one or more communicating paths communicating a lower region inside the filter case with the outlet . <EOS>