In this paper, the characteristics of lubrication and wear phenomena of journal bearing with respect to film parameter and Sommerfeld number variation are investigated experimentally and the design criterion for the hydrodynamic journal bearing is presented to avoid wear and seizure. Experimental work is performed with various rotating speed and load, and lubricant is used synthetic oil and mineral oil. By the results of the experiment, it is found that friction coefficient is decreased as Sommerfeld number is decreased, and that wear phenomenon is observed when Sommerfeld number is below $9$ imes$10^{-4}$</TEX> and there are much alike in wear properties between synthetic and mineral oil.