To more surely remove an odor from water to enable the water more effectively reused, when cleaning water after car washing discharged from a car washer is going to be reused.

This car washer waste water cleaning device 13 is provided with a sterilizing device 15 for sterilizing water 3 discharged from a car washer 1, a separator 17 for separating a surfactant 16 and oil components mixed into the water 3 sterilized by the sterilizing device 15 from the water 3, a filter 18 for filtering the water 3 from which the surfactant 16 and oil components have been separated by the separator 17, and a water return device 19 for feeding the water 3 filtered by the filter 18 to the car washer 1.