This paper describes a new type variable inductor and its applications to reactive power controller for use in electric power system. We present a 6.6kV-300kVA magnetic flux control type reactor (MFCR) for reactive power compensator based on the EIE-core type variable inductor. The MFCR has good control characteristics, simple structure and high reliability, low level harmonic currents , high-speed response and low cost.