An injection molding composition includes a ferrite powder which is a collection of ferrite particles, a first binder and a second binder, wherein a softening point of the second binder is lower than that of the first binder, a weight and a specific surface area of the ferrite powders are represented by Wp and S, and a weight and a density of the first binder and the second binder is represented by Wb1, Wb2, and Db1, Db2, and a hypothetical thickness Tb1 of the first binder is 0.6 to 3.0, and a hypothetical thickness Tb2 of the second binder is 5.0 to 16.0. In the composition, it is preferable that coated ferrite particles covering the outer circumference of the ferrite particles with the first binder and the second binder exist. Tb1 [nm]=(Wb1×103)/(Db1×Wp×S)  formula (1) Tb2 [nm]=(Wb2×103)/(Db2×Wp×S)  formula (2).