In order to form β-Ti-H alloy and γ hydride, the movement of hydrogen in titanium have been studied, employing T. G. A. method. It has been found that 1) the reaction of Ti-hydride formation is controlled by hydrogen diffusion in Titanium. 2) the activation energy of the reaction is 4.6㎉/㏖. 3) Surface contamination of titanium metal retards the reaction markedly.