PURPOSE: To treat the surface of a substrate wet with high quality by supplying liquid while rotating a nozzle as a wet treating method for the surface of the substrate thereby decreasing the mechanical forces acting between the liquid and the surface of the film to be treated on the substrate.

CONSTITUTION: A substrate 1 is attracted and held by a vacuum chuck 5, and a nozzle 9 is disposed above the substrate 1 in parallel proximity with the substrate 1. A revolving shaft 10, that is, the nozzle 9 is rotated and chemical liquid 3 is supplied to the nozzle 9 through a chemical liquid supply pipe 12 then through a stationary block 11 and the shaft 10. Thus the liquid 3 is supplied uniformly over the entire surface of the substrate 1 through the hole 9a of the nozzle 9.