The present invention relates to a clothing treatment device comprising: a tub body for providing a space in which water is stored; a tube cover that forms the upper surface of the tub body; an introduction opening provided to penetrate the tub cover; a door provided on the tub cover so as to open/close the introduction opening; a drum rotatably provided inside the tub body so as to contain clothing introduced through the introduction opening; a storage portion provided on the door so as to provide a space in which an additive is stored; a channel portion for guiding at least a part of water, which moves from the tub body toward the tub cover when the drum rotates, to the storage portion; and a discharge portion for discharging the additive inside the storage portion and the water, which has been introduced into the storage portion, to the tub body.