Provided is a reactor including a coil having a pair of winding portions; and a ring-shaped magnetic core, the magnetic core including: a pair of inner core portions arranged inside of the winding portions; and a pair of outer core portions respectively arranged outside of one end and outside of another end in an axial direction of the winding portions, the reactor including a non-magnetic reinforcing member that is arranged between the pair of winding portions and is coupled to the inner end surfaces of the pair of outer core portions. An axial rigidity of the reinforcing member is 2×107 N/m or more. Here, the axial rigidity is a value obtained by multiplying the cross-sectional area of the reinforcing member perpendicular to the axial direction of the winding portions and the Young's modulus of the reinforcing member, and dividing the result by the length of the reinforcing member.