A wafer-processing apparatus includes: multiple discrete units of reactors disposed on the same plane; a wafer-handling chamber having a polygonal shape having multiple sides corresponding to and being attached to the multiple discrete units, respectively, and one additional side for a load lock chamber; a load lock chamber attached to the one additional side of the wafer-handling chamber; multiple discrete gas boxes for controlling gases corresponding to and being connected to the multiple discrete units, respectively; and multiple discrete electric boxes for controlling electric systems corresponding to and being detachably connected to the multiple discrete units, respectively, wherein the gas boxes and the electric boxes are arranged alternately as viewed from above under the multiple discrete units, and the electric boxes can be pulled out outwardly without being disconnected from the corresponding units so that sides of the gas boxes are accessible.