A core body of a reactor includes an outer peripheral iron core composed of a plurality of outer peripheral iron core portions, at least three iron cores coupled to inner surfaces of the plurality of outer peripheral iron core portions, and coils. Gaps, which can be magnetically coupled, are formed between one iron core and another iron core adjacent thereto. The reactor further includes a fixture which extends through the interior of the core body in a region between the outer peripheral iron core and the gaps to fasten opposite ends of the at least three iron cores to each other.