Ion-induced secondary electron emission characteristics (γ_i) is very most important to evaluate protecting material for ac-Plasma Display. Automatic measuring system results in the repeatable result with stability, and expected to have new information about the protecting materials by the detailed analysis for the obtained results. In the present paper, we tried to make the measuring system, which is controlled by the personal computer. We examined the point on mounting, and designed nano-current circuit, which consist of I-V conversion circuit and isolation amplifier.