To provide a long-length discharge nozzle for a process liquid excellent in attachability/detachability and maintenance performance, and not deflecting without a beam type nozzle holding mechanism.

A deflection correction mechanism 74 mounted to the discharge nozzle 64 for a process liquid includes: first and second intermediate joint parts 78 and 80 projectingly provided on a reinforcing surface 68a at first and second intermediate points P_M1 and P_M2 of a nozzle header pipe 68; a central joint part 76 projectingly provided on the reinforcing surface 68a between the first and second intermediate joint parts 78 and 80 of the nozzle header pipe 68, for example, at a center point Pc in a longitudinal direction; a first connecting rod 82 laid between the central joint part 76 and the first intermediate joint part; and a second connecting rod 84 laid between the central joint part 76 and the second intermediate joint part 80.