A wafer scrubber apparatus is disclosed, including a chamber, and holder connecting to a spindle disposed in the chamber, wherein the holder supports a wafer, and a gas purge pipe disposed at the top of a wall of the chamber, wherein the gas purge pipe comprises a plurality of gas injection holes facing downward to purge gas along the chamber wall making water flow along the chamber wall more smoothly and more quickly for preventing the water from scattering back to the wafer.