The doping dependence of the in-plane resistivity ρa(T) and the out-of-plane resistivity ρc(T) have been systematically measured for the triple-layered system, Bi2Sr2Ca2Cu3 O10+δ (Bi-2223). In comparison with the bilayered system, Bi2Sr2CaCu2O8+δ (Bi-2212), we found in Bi-2223 that the superconducting transition temperature Tc and pseudogap formation temperature T*, below which ρc shows a typical upturn, do not change from their optimum values in the overdoped region, even though doping actually proceeds. This result suggests that inequivalent hole doping occurs between the outer and inner planes. In the overdoped region, the carriers are mostly doped in the outer plane and the inner plane remains at an optimum doping level.
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