In this paper, electrostatic drop formation characteristics in the use of water-based ink are reported for applications to ink jet devices. In order to make clear experimentally the electrostatic uniform drop formation phenomenon, applied voltage, flow rate, nozzle diameter and distance between the nozzle tip and the electrode are widely varied. In addition, liquids having different values of electric conductivity, surface tension and viscosity are used, and the experiments are carried out to examine the effects of these factors on the uniform drop formation. Then, the relations among the various factors governing the uniform drop formation phenomenon are studied by a dimensional analysis.