A single- and dual-chamber module-attachable wafer-handling chamber includes: a wafer-handling main chamber equipped with a wafer-handling robot therein, and adaptors for connecting process modules to the wafer-handling main chamber. The adaptors are detachably attached to the sides of the wafer-handling main chamber, respectively, and the process modules are detachably attached to the adaptors, respectively, so that the process modules can be attached to the wafer-handling main chamber, regardless of whether the process modules are of a single-chamber type or dual-chamber type.