To provide a reactor apparatus capable of easily reducing noise without changing material or structure of a reactor.

If an AC current is applied to each coil 2 of the reactor apparatus 200, a magnetic pole generated at an iron core alternates to cause a state where a current value is 0 (zero). So, generation and disappearance of polarity of the iron core alternates at all times, for repeated shrinkage and restoration of the reactor. This phenomenon alternates attracting force (X) for contracting the reactor and restoring force (Y) for restoring the reactor. The U-shaped iron cores 4 adjoining each other that are coupled by a coupling means 30 cancel each other mutual oscillations generated by the attracting force (X) and the restoring force (Y). So, the U-shaped iron cores 4 coupled each other can suppress occurrence of oscillation by canceling the generated mutual forces (X) and (Y). As a result, generated noise is reduced.