Micro electrical discharge machining (MEDM) is a promising technology for fabricating micro-parts on a variety of materials. An RC circuit is suitable for MEDM because it produces low pulse width and relatively high peak current. However, it is not well understood how circuit elements affect machining characteristics of MEDM. In this paper, the effects of circuit elements on MEDM of micro-holes and the relation between characteristic variables of process and machining characteristics was investigated. Since the discharge inductance causes an increase in electrode wear and machining time, it should be minimized in MEDM. From this study, it should be less than a few ${mu}H$. The machining time also increases with increasing the charging resistance. If the charging resistance is less than a few hundreds ${Omega}$, however, continuous arc discharge occurs and the machining speed is markedly reduced.