Provided is a reactor including a coil that has wound portions formed by winding a winding wire, and a magnetic core that includes inner core portions arranged inside of the wound portions and outer core portions arranged outside of the wound portions. The reactor includes an outer resin portion covering at least outer surfaces of the outer core portions. A terminal platform is formed in one piece protruding on the outer surface of an outer resin portion among the outer resin portions and has fastening portions configured to fasten terminal fittings connected to end portions of the winding wire to terminals of an external wiring. A fixing portion is formed in one piece on the terminal platform and fixes the reactor to an installation target. The terminal platform and the fixing portion are integrated and the thickness of the terminal platform is less than that of the fixing portion.