A reactor (2) includes a bobbin (10). The bobbin is a resin-made bobbin, and has a pair of flanges (12a, 12b) that face each other. Coils (3) are wound around the bobbin between the pair of flanges. Each of a pair of plates (20) is bridged from the flange on one side, which is one of the pair of flanges, to the flange on the other side, which is one of the pair of flanges. The pair of plates abuts on circumferences of the coils between the pair of flanges. A resin cover (40) covers one of two outer peripheries of the coils. The two outer peripheries are defined by the pair of plates.