The present invention is to provide a toner for developing electrostatic images having excellent fixability, peelability, shelf stability (blocking resistance), printing durability, printing durability after being left at high temperature and thin line reproducibility. A toner for developing electrostatic images, comprising colored resin particles comprising a binder resin, a colorant and a wax, wherein the wax contains a natural sunflower wax, and wherein the natural sunflower wax has an acid value of 10 mg KOH/g or less, and a content of the natural sunflower wax is in the range from 1 to 10 parts by weight with respect to 100 parts by weight of the binder resin.