Disclosed is a tilted drum type washing machine, in which an internal structure is improved to prevent a contact between a drum and a lip of a gasket. The present invention includes a cabinet having an entrance at a front side for inputting/outputting a laundry, a door opening/closing the entrance, a tub installed slant in the cabinet to hold water, a drum in the tub to hold a detergent and the water, a gasket between the door and the tub, the gasket bringing the door airtight to prevent the water from leaking outside, a lip on an inner circumference of the gasket to prevent particles from being put in a space between the tub and the drum, and a support member preventing the lip from drooping to prevent an interruption between the lip and the drum. And, the support member includes a reinforcement rib on an inner circumference of the tub to support an inner lateral side of the lip or a protrusion at the inner lateral side of the lip.