A washing machine includes a cabinet, a tub, a drum, a drawer disposed within the cabinet to hold detergent, a drawer housing configured to insert into and withdraw from the cabinet, a water supply guide flow channel for supplying water passed through the drawer into the tub, a top cover housing covering an open top of the cabinet and defining a receiving space above the cabinet, a detergent mixer disposed in the receiving space, and a discharge guiding mechanism. The detergent mixer includes additive cartridges that accommodate liquid additives, additive pumps corresponding to the additive cartridges, and a flow channel box including pump intake paths that guide the additives from the additive cartridges to the additive pumps and pump discharge paths that guide the additives discharged from the additive pumps. The discharge guiding mechanism guides the additives discharged from the pump discharge paths to the water supply guide flow channel.