A toner for developing electrostatic charge images that exhibits superior fixability at low temperature so as to realize satisfactory fixing performance even with less energy, that exhibits high stress resistance so as to be free from blade contamination by molten toner, and that exhibits excellent performances in any environmental conditions. In particular, a toner for developing an electrostatic charge images, comprising at least a binder resin, a colorant and a charge control agent, wherein a low-molecular-weight polymer having functional groups is used at least as the charge control agent and a cycloolefin copolymer resin is used at least as the binder resin.