A core main body includes: an outer peripheral iron core, and at least three iron cores coupled to an inner surface of the outer peripheral iron core, in which a gap is formed between adjacent iron cores among the at least three iron cores, the gap being magnetically connectable, and a plurality of notches are formed on an outer circumferential surface of the outer peripheral iron core, the plurality of notches extending in an axial direction of the outer peripheral iron core. The reactor includes such a core body.