The method for manufacturing core-shell structure fine particles, includes adding metal salt into an aqueous medium containing shell particles A and core particles B to thereby attach the shell particles A to the surface of each of the core particles B and the toner contains the core-shell structure fine particles. (1) The zeta potential of the core particles B and the zeta potential of the shell particles A are the same polarity. (2) |Zeta potential of the core particles B when adding metal salt| (Median diameter based on the volume of the shell particles A).