Magnetic resin composition for injection molding, and injection molded body for magnetic shields

A magnetic resin composition for injection molding comprising a thermoplastic resin (A) that has a melting point of 100° C. to 400° C. and magnetic particles (B), wherein

• as the magnetic particles (B), scale-like particles that are formed of an Fe—Si—Al alloy are used, and a mass ratio of the thermoplastic resin (A) to the Fe—Si—Al alloy, that is, thermoplastic resin (A)/Fe—Si—Al alloy is 10/90 to 15/85, and
• conditions (1) and (2) described below are satisfied when, in order to form the magnetic resin composition for injection molding into a shape of a sheet, the sheet is prepared by uniformly applying a pressure of 15 MPa from above one main surface side of a sheet to be formed over 1 minute at a temperature of the melting point of the thermoplastic resin (A)+15° C., and in a cross-sectional surface in a thickness direction of the sheet, a region with a length of 0.125 mm and a thickness of 0.090 mm is subjected to image processing with a micrograph at a magnification of 2500:
• (1) a total area of the magnetic particles (B) subjected to image processing is 40% to 65% of the area of the image processing region,
• (2) a number of the magnetic particles (B) subjected to image processing is 200 to 500.