A reactor includes: a coil having winding portions; a magnetic core including inner core portions and a pair of outer core portions sandwiching the inner core portions; end surface interposed members including main body portions between end surfaces of the winding portions and outer core portions, and resin filling holes communicating with interiors of the winding portions; inner resin portions where spaces between inner circumferential surfaces of the winding portions and inner core portions are filled; and outer resin portions covering part of the outer core portions and are connected to the inner resin portions through the resin filling holes. At least one of the pair of outer core portions and an end surface interposed member are formed integrally. The end surface interposed member includes a core holding portion extending to the outer core portion side and interposed between the core holding member and the main body portion.