A laminated step-down piezoelectric transformer has a driving portion 11 and an electric power generating portion 12 disposed on both end portions of an elongated plate. These portions are formed by alternately laminating piezoelectric members 111 and internal electrodes 112 . . . interposed by an insulating portion respectively. The piezoelectric members 111 of the driving portion 11 are thicker in thickness than that of the electrical power generating portion 12. The transformer is driven with a second-order mode in the longitudinal direction so that the transformer has a high transformation efficiency. Impedance matching can be realized easily. The piezoelectric transformer is safe in operation by separating the input and the output from each other.