Magnetic particles (cobalt ferrite) having a micrometer-order average particle diameter and similar particle diameters. A cobalt ferrite precursor is heated in the presence of a sulfite, thereby obtaining intended cobalt ferrite magnetic particles.

Disclosed is an electrostatic charge image developing toner including: toner base particles containing at least a binder resin and a magnetic material; and an external additive, wherein the binder resin contains a crystalline resin; and the external additive contains strontium titanate particles doped with metal elements other than titanium and strontium.