words the switching element 403 is closed at a predetermined hydraulic pressure and more and it is opened at a predetermined hydraulic pressure and less this switching element 403 closes the backflow hole 122 when the drum washing machine 10 conducts the draining process as it is operated by the high pressure washing water generated by the drain pump 181 therefore it prevents the washing water drained out of the siphon brake hole 402 from being flowed into the dispenser 120 accordingly the drainage performance of the drum washing machine 10 is improved here the position of the switching element 403 is not restricted to one side of the backflow hole 121 in the dispenser 120 but the switching element 403 may be formed in any selected point of the backflow hose 401 in order to selectively open close the backflow hose 401 further a check valve or an electromagnetic valve may be used as a switching element 403 hereinafter the operation of the siphon brake device 400 will be explained first the washing water stored in the tub 300 is flowed into the drain pump 181 through the drain pipe 180 when the drum washing machine 10 begins the draining process after that the washing water runs through the drain hose 182 as the drain pump 181 operates and some of the washing water is flowed into the siphon brake hole 402 formed in the drain hose 403 the drained washing water moves toward the.