In this study, we aim at control of the time from ignition of gunpowder to projectile launch with Electrothermal-Chemical gun (ETC gun). ETC gun uses electro energy at ignition of gunpowder from condenser bank. Therefore delay time of discharge is stabilize. Because the variation in ignition speed and combustion speed becomes small. In this paper, the. experiment changed the charge voltage of a condenser bank. Therefore, the voltage and current at the time of ignition also change. We clear delay time for variation of voltage and current at the time ignition. Furthermore, We examine the current and voltage which the minimum delay time.