There is provided a resin magnet material that has excellent flame retardancy, produces only a small amount of toxic substances when ignited, and yields very few molding defects; as well as an electron beam adjustment apparatus in which this resin magnet material is used. To achieve this object, a first invention comprises a flame-retardant resin magnet material obtained by adding (Z) an alnico-based magnetic powder or a ferrite-based magnetic powder to a flame-retardant resin composition that is itself obtained by adding heat-resistant aluminum hydroxide and antimony trioxide to a polyamide resin in the following amounts: (A) per 100 weight parts polyamide resin, (B) X1 weight parts heat-resistant aluminum hydroxide with a decomposition temperature of 280°C or higher (where 10 weight parts