A toner containing toner particles having a core-shell structure containing a binder resin, a colorant and a release agent. The toner particles are prepared by dissolving or dispersing at least one of the binder resin and a precursor thereof in an organic solvent or a polymeric monomer and reacting the resultant in an aqueous medium for reaction, wherein the toner satisfies the following relationship: .DELTA.Tm=Tm1-Tm2>10 .degree. C., wherein Tm1 represents half efflux temperature of the toner and Tm2 represents half efflux temperature of a toner which is prepared by melting and kneading the toner particles and wherein a content of the release agent existing close to the surface portion of the toner particles is from 7 to 30% by volume based on an entire portion close to the surface portion of the toner particles when the content is determined by Fourier Transform Infrared Spectroscopy Attenuated Total Reflection (FTIR-ATR) method.