A reactor includes a core body having an outer peripheral iron core. A least three iron cores are in contact with or connected to an inner surface of the outer peripheral iron core, and coils are wound onto the at least three iron cores. Gaps are formed between two adjacent iron cores from among the at least three iron cores or between the at least three iron cores and a central iron core disposed at the center of the core body, through which gaps the iron cores are magnetically connectable. The reactor also includes an end plate fastened to at least one end of the core body such that the end plate is shaped to correspond to the outer peripheral iron core. The end plate is formed from a plurality of end plate parts.