To obtain a ferrite magnetic core, having a low-temperature coefficient of large μi which is not smaller than 2,500 and the changing rate of its μi is small over a wide temperature range.

The ferrite magnetic core is made of Fe2O3 of 53 to 54 mol.%, ZnO of 16 to 22 mol.%, and MnO for the balance as the main components, and has SiO2, CaO, and Nb2O5 as the auxiliary components. Further, the ferrite magnetic core has its initial permeability not smaller than 2,500 at 20°C, and has a rate of change of its initial permeability which ranges from -10% to +10% at -20°C to 100°C, when its initial permeability at 20°C is used as the reference.