Modified nigrosine which has satisfactory dispersibility in resin and which reduces the residual aniline amount is offered, and its production method is also offered. Moreover, toner for developing electrostatic charge images is offered, which uses modified nigrosine colorant that resolves the aforementioned problems, which has excellent charge-imparting properties, which exhibits no fogging, which experiences no scattering of toner inside the developing apparatus, and which has little fluctuation of image density.Modified nigrosine, which is nigrosine (b) that has been modified by rosin-modified resin (a) with an acid value of 110 or less.