that the sterilization function due to the electric current between the first electrode 130 and the second electrode 140 can be exhibited and then the sterilizer 100 operates in the first mode during the rinsing process in which the density of the detergent is reduced such that the ag ions can be supplied to the washing water in further another embodiment the washing machine can operate in a washing mode in which the water reservoir and the drum are washed separately from the washing and rinsing processes the washing mode corresponds to a dedicated washing process of removing biofilms formed in the water reservoir and the drum due to the propagation of bacteria that is in a state where washing water is supplied to the water reservoir without the laundry the circulation pump 8 operates to circulate the washing water and the sterilizer 100 operates in the second mode or the first mode in order to improve the washing effect by the circulated washing water a salt supply unit not shown can be provided to supply salt to the supplied water the salt supply unit can be additionally provided to the washing machine or can also be provided to the detergent box 6 b of the detergent supply apparatus 6 see fig1.