In order to make the numerical analysis model for friction coefficient and surface roughness of a rolled material in cold rolling, the experimental equations for the unknown parameters in the model of cold rolling lubrication are obtained from the analyses of experimental results for characteristics of boundary lubrication and surface roughness in cold rolling of steel sheets which were reported formerly. Also, applying these experimental equations to the model of cold rolling lubrication gives the numerical analysis model for friction coefficient and surface roughness of a rolled material. Then, the values calculated by the numerical analysis model are compared with the ones measured by the cold rolling experiments. Moreover, the effects of surface roughnesses of roll and an initial material on friction coefficients and surface roughnesses of the rolled material in cold rolling are analyzed by the numerical analysis model. As a result, the lubrication mechanism in the cold rolling experiments reported formerly has been discussed and clarified.