A reactor includes an outer peripheral iron core composed of a plurality of outer peripheral iron core portions and at least three iron core coils arranged inside the outer peripheral iron core. The at least three iron core coils are composed of iron cores coupled to the plurality of outer peripheral iron core portions and coils wound onto the iron cores. Gaps, which can be magnetically coupled, are formed between adjacent iron cores. The reactor further includes connection parts for connecting the plurality of outer peripheral iron core portions to each other.