A method for producing a magnetic particle forming a magnetic material for absorbing electromagnetic waves comprises the steps of mixing an organometallic complex or a metal salt with a chain polymer and dissolving the mixture in a solvent (step S1); raising the temperature of the mixture to reaction temperature (step S2), carrying out a reaction at the reaction temperature (step S3); and forming the magnetic particle having a structure that the periphery of each fine particle formed from the organometallic complex or the metal salt is surrounded by the chain polymer and recovering the formed magnetic particle after the reaction (step S4). The magnetic particle has a nanogranular structure to become a magnetic material for absorbing electromagnetic waves. Such a magnetic particle is produced by a wet reaction. Thus, a larger amount of magnetic particle can be produced by one reaction.