Disclosed is a developer containing toner and carrier, the toner containing as a binder resin a polyol resin having a plurality of OH groups in a molecule chain having an EX/OH ratio between epoxy groups (EX) and OH groups (OH) of 0.990 to 1.010. The rotational speed .alpha., pitch .beta. and conveyance path length .gamma. of an stirring and conveying unit satisfies 1.0.times.10.sup.6.ltoreq..alpha..times..beta..times..gamma..ltoreq.16.0.- times.10.sup.6. Toner base particles having an electrostatic property satisfies 1.5<[Q.sup.B/M.sub.3600]/[Q.sup.B/M.sub.180]<2.5, toner having an electrostatic property satisfies 0.7<[Q.sup.T/M.sub.3600]/[Q.sup.T/M.sub.180]<1.3, the external additive comprises two types of fine inorganic particles having different resistance values, wherein the particle size distribution Y and added amount X of the fine inorganic particles with smaller resistance satisfy 0.1.ltoreq.x.ltoreq.2.0, and Y.ltoreq.2.6.times.10.sup.-3X+0.0048.