The blade member of the invention is composed mainly of silicone rubber and contains as an additive component at least one selected from the group consisting of ultra-high molecular-weight-polyethylene, carbon nanotube, and fullerene. It is thus possible to decrease the coefficient of friction of silicone rubber in a practical range and without detrimental to its flexibility or other physical properties to let the developing blade slip off more, thereby diminishing the amount of abrasion of the rubber and improving on the robustness of the developing blade without detrimental to image quality. Decreasing the coefficient of friction to let the developing blade slip off more has additional advantages: a decrease in the force of contact of the developing blade with a developing roll, which contributes more to energy savings resulting from the size reductions of a driving motor, and making the developer equipment compact.