A magnetic circuit component molding device for integrally molding a compound a center yoke with a ring-shaped magnet includes top and bottom press vertically arranged at opposed positions. A ring-shaped magnet is place on a bottom die between top and bottom press. The top and bottom press compress the compound against the ring-shaped magnet ring with a vertical pressure. A holder unit, separated in plural segments, having tapered outer circumferences is provided around the ring-shaped. A holder presser having a tapered inner circumference is mounted on the holder unit as tapered portions thereof are engaged together. A portion of the vertical pressure, when the top press compresses the compound, is transferred by springs 10 to the holder presser, and is amplified by the tapered portions and applied to the outer circumference surface of the ring-shaped magnet by the holder unit.