In a toner having toner particles having at least a binder resin and a colorant, the binder resin in the toner contains at least i) a vinyl resin formed of a vinyl resin having at least a carboxyl group and a vinyl resin having at least an epoxy group, and having a cross-linked structure formed by the reaction of the carboxyl group of the former with the epoxy group of the latter, and ii) a copolymer having an aliphatic conjugated diene compound as a monomer component; and the binder resin in the toner has a THF-insoluble matter in a content of from 0.1% by weight to 60% by weight, and the copolymer having an aliphatic conjugated diene compound as a monomer component is incorporated in an o-dichlorobenzene-soluble matter of the THF-insoluble matter. This toner has superior developing stability and running performance in high-speed machines, and can keep fixing separation claws from contamination.