A drum-type washing machine includes a washing water supply apparatus providing a liquid passage from a water outlet of a detergent reservoir to an inner space of a tub. The washing water supply apparatus employs a bubble dissipation device for preventing bubbles generated in a tub from reaching an inlet bellows and entering a detergent reservoir. The washing water supply apparatus includes a water supply duct formed at an upper part of the tub; an inlet bellows, one end of which is coupled to the water outlet of the detergent reservoir and the other end of which is connected to the water supply duct, for supplying a liquid to the tub; and a bubble dissipation device, vertically installed along the liquid passage of the washing water supply apparatus, for preventing bubbles generated in the tub from entering the detergent reservoir. The bubble dissipation device includes a float movably disposed in the washing water supply apparatus to travel a predetermined vertical distance along the washing water supply apparatus between a seated stated and a raised state, under a force of a forming air bubble, for blocking the liquid passage when a bubble is generated and allowing the liquid of the washing water supply apparatus to drain into the tub when no bubble is generated. An air escape hole having a small cross-section, for allowing air trapped by the float to escape slowly back into the tub, provides communication between the inner space of the tub and a space created when the float is in the raised state.