To provide a wafer processor for satisfactorily processing wafer in a series of first and second processings.

A first wafer processor unit 1 for a chemical liq. treatment (first wafer processing) comprises a first spin chuck 11, first cup 12 and chemical liq. feed nozzles 13, 14. A second wafer processor unit 2 for a rinsing-drying treatment (second wafer processing) comprises a second spin chuck 31, second cup 32 and rinse liq. feed nozzles 33, 34 and is disposed above the first unit 1. A movable atmosphere screen 4 is disposed between a working position between the first and second units 1, 2 and waiting position at the side of the first cup 12 to thereby screen the atmospheres in the first and second units 1, 2. The first and second spin chucks 11, 31 move up and down relatively to transfer wafers W.