Gibrat's Law has been widely tested in the empirical literature. Different arguments also rise in these studies. This thesis reexamines Gibrat's Law by the regression method. Information from previous studies show the number of employees is the proxy for the size of the firm, and the growth rate of employees measures the growth rate of firm size. Ordinary Least Square is applied to analyze the panel data from seven European countries' enterprises. Empirical results might reject the existence of Gibrat's Law.