PURPOSE: To provide a composition for plastic magnet, which can be subjected to injection molding even if a metal mold is not subjected to temperature control and is capable of making a molded material release easily from the metal mold even if a draft angle is not provided on the metal mold.

CONSTITUTION: A composition for plastic magnet, which is composed of magnetic powder, which is a ferrite, and a resin binder consisting of an ethylene ethyl acrylate copolymer or a polyethylene, is made an extrusion test using a flow tester under each condition of an extrusion pressure of 50kg/cm2, the diameter of 1mm of an orifice, the height of 2mm of the orifice and a preheating time of 120 seconds. In that case, an extrusion flow rate is controlled so as to have a fluidity that it is 0.005 to 0.05ml/second at a testing temperature of 120°C and is 0.07 to 0.7ml/second at a testing temperature of 200°C and a molding shrinkage factor is controlled in such a way that it is 0.2 to 2.5%.