The automobile industry is conducting various studies to improve vehicle fuel efficiency. Recent research involve the reduction of loss of an engine auxiliary device, and in particular, research related to an oil pump of an engine lubrication circuit. A gerotor oil pump produces cavitation inside the chamber as the rotational speed increases. Since cavitation causes damage to the engine and pump, an analysis of cavitation occurrence is required. In this study, the reliability of the analysis results was secured by parallel experimenting and analyzing the gerotor oil pump. The cavitation occurrence was analyzed through 1D simulation and the following conclusions were obtained. Lower oil temperature and higher pump rotation speed result in higher amount of cavitation generated. In addition, it was confirmed that cavitation generation increased as viscosity of the oil decreased.