A new method for analyzing the kinetics of CVD reactions is proposed using area-controlled CVD. Catalyst particles were set at the dead end of a narrow straight tube. Water vapor generated at the catalyst from H-2 and CO2 was fed into the reaction zone to react with TiCl4, which diffused from the opposite side. Then, TiO2 was formed and deposited on the tube surface. The rate-controlling step in the CVD process was clarified by investigating the dependence of deposition width on the inner diameter of the reaction tube. From the experimental results, it is found that diffusion and surface reaction-step were the rate-controlling step at 373-393 K and 413-513 K, respectively. It is elucidated that the value of rate constant of surface reaction can be evaluated as 1.5 x 10(-3) m s(-1), which is almost constant in the temperature range, 413-513 K, The value is so small that estimation by using the step coverage method can not give a reliable value.