To obtain a compsn. excellent in the magnetic characteristics, shape freedom moldability, and mechanical strengths, by mixing a magnetic powder with a binder having the main component of an unsatd. polyester resin.

A magnetic powder has an anisotropy magnetic field (HA) of pref. 50 kOe or more; the powder contains pref. 50% or more of powder with a particle dia. of 100 μm or less. A resin binder pref. contains a peroxide which gives a curability at a temp. of 150°C or below; moreover the binder is pref. a liquid-state at a temp. of 150°C or below. The compsn. may be cured, pulverized, and mixed with a thermosetting resin or a thermoplastic resin. The resin binder is usually added in an amt. from 5 pts.wt. to 50 pts.wt. relative to the magnetic powder. Molding is carried out with a thermosetting resin molding machine such as an injection molding machine or a transfer molding machine, especially pref. carried out with an injection molding machine.