Disclosed is a toner for developing electrostatic images comprising a colored resin particle containing a binder resin, a colorant and a softening agent, and an external additive, wherein the colored resin particle contains a diester compound represented by the following general formula (1) as the softening agent, and a content of the diester compound is in the range from 1 to 15 parts by mass with respect to 100 parts by mass of the colored resin particle, and the toner has a softening temperature “Ts” of 55 to 70° C., a flow starting temperature “Tfb” of 80 to 100° C. and a glass transition temperature of 40 to 70° C. in a flow tester: wherein, R1 is an ethylene group or a trimethylene group; and each of R2 and R3 is independently a linear alkyl group having 11 to 25 carbons.