To provide a silver ion water generator for a washing machine, which can reduce the consumption and consequently extend the life span of a cartridge for generating silver ions, and in addition which can be retrofitted to all washing machines in common without regard to model.

The silver ion water generator 3 to be installed at the midstream of a water feeding system to a washing machine 1 comprises a power source independent of the power source 30 of the washing machine. A power source control unit 4 is connected to the independent power source for detecting the termination of the washing processes of the washing machine to switch on the power source of the silver ion water generator as well as detecting the termination of all the processes of the washing machine to switch off the power source of the silver ion water generator.