When a step voltage is applied to an electrostrictive transducer, the decay of the terminal current is not monotone. Although this phenomena caused by piezoelectric reaction has already been confirmed for the thickness mode, [C. Kasai, D. Okuyama and Y. Kikuchi, “Transient Response Analysis of Piezoelectric Transducers Using Reflection and Transmission Coefficients at Their Surfaces,” Electron. Commun. Jpn56‐A(3), 19 (1973)] it has not been confirmed for the longitudinal mode using transversal effect. This paper presents an analytical method for longitudinal mode that is similar to that used for the thickness mode, and also shows that the numerical calculations based on this method approximately agrees with the experimental results for the samples of electrostrictive columnar and rectangular plate. By these results, it became clear that the current waveform depends on the electromechanical coupling factor of the transducer material and the time constant of the driving circuit of the transducer.