PURPOSE: To prevent the scattering of dust to each section brought into contact with the rear of a wafer by the conveyance of the wafer by washing the central section of the rear of the wafer, to which the coating and developing treatment of a resist is executed, by a solvent.

CONSTITUTION: A wafer 3 to which the coating formation and developing treatment of a resist film is executed is conveyed by a wafer conveyor 13, sucked by a suction chuck 15 for supplying the wafer, and forwarded into the recessed section 2 of a wafer suction holder 1 from a wafer conveying port 18 and positioned. The wafer is sucked under a vacuum through suction grooves 5, and held. An opening at an upper end is closed by a cover body 10 while the wafer conveying port 18 for the wafer conveying port 18 is closed. A solvent 19 is radially injected uniformly toward the central section of the rear of the wafer 3 from a washing nozzle 6 installed to a washing vessel 7, and fouling sections 9 such as the resist, a developer, etc., on the rear of the wafer 3 are washed. Washing is completed, air is injected onto the rear of the wafer 3 through openings 4 from an air supply nozzle 11, and the wafer is dried.