Electrical power generation devices that use lead zirconate titanate piezoelectric (PZT) elements have been developed to convert structural vibration energy into electrical energy. We have reported the effects of vibration loads on the power-generation characteristics of a PZT element doped with niobium (Nb), and have proposed the use of laminated PZT elements to significantly improve the power-generation characteristics of PZT elements. This paper describes an experimental and analytical study conducted to clarify the power-generation characteristics of the laminated PZT element doped with Nb under vibration loads. In the experimental study, the effects of the number of layers of the laminated PZT element, the loads and frequencies of the vibration loads and load resistances of voltage measurement circuit on the power-generation characteristics of the laminated PZT element are evaluated by vibration tests. In the analytical study, theoretical formulas on the power generation characteristics of the PZT element under the vibrational loads are derived by considering the equivalent circuit model consisting of the laminated PZT element, the load resistances and the voltmeter. In addition, the experimental results on the generated voltage and the electric power in the laminated PZT element are compared with analytical values using the theoretical formulas. The validity of the power generation theory of the laminated PZT elements under the vibrational loads is evaluated. From experimental results, it is confirmed that the laminated PZT element can dramatically improve the power generation characteristics as an electrical generator using the PZT elements, and the power-generation characteristics of the laminated PZT element depend largely on the number of layers of the PZT element, the loads and frequencies of the vibrational loads and the resistances of the measurement circuit. From analytical results, the validity of the power generation theory of the laminated PZT elements under the vibrational loads is confirmed by comparison of the experimental results and the analytical results.