A water leakage detecting device for effectively detecting water leakage and sensing malfunctions in the device is disclosed. The device includes a base retaining water leaked from a tub, a detector detecting whether leaked water is retained in the base, a first signal generator outputting a signal, when the detector detects the leaked water, a second signal generator outputting a signal, when the detector does not detect the leaked water, and a controller deciding whether to drain the leaked water and determining whether the water leakage detecting device has a malfunction.