A laminate type organic electrophotographic photoconductor uses a thick undercoating layer as an intermediate layer for reducing the influence of a conductive substrate on a charge generation layer. An organosilicon coupling agent is bonded to the surfaces of small particles of titanium oxide, zirconium oxide, aluminum oxide or cerium oxide, at an Existence Ratio represented by the peak intensity ratio (Si2p/Me2p, Me=Ti, Zr or Al) or (Si2p/Ce3d) of from 0.15 to 0.6 of a bonding energy spectrum measured by X-ray photoelectron spectroscopy. The metal oxide small particles, the surfaces of which have been treated mechanochemically, are cleaned to reduce the ionic impurity concentration of the undercoating layer to below 1 ppm. The cleaned metal oxide small particles are dispersed into the polyamide copolymer binder resin for the undercoating layer. The undercoating layer produced in this manner results in a electrophotographic photoconductor whose electrical properties are constant despite environmental changes and repeated use. The electrophotographic photoconductor also resists residual potential rise after repeated use, and also resists image defect formation despite changes in environmental conditions and operating conditions.