Most important problem involved in the practical use of hydrogen car is hydrogen storage materials. If it uses a fuel cell that generates electricity through reaction between hydrogen and oxygen, it does not matter. However, if method is that hydrogen is sprayed to internal-combustion engine, it does matter. Now hydrogen storage tank with highest possibility is method using metal hydride. Metal hydride is that reversible reaction between metal and hydrogen make new form of compound. Now Hydrogen storing technology using Hydrogen storage compound metal comes to practical use step in the side of technical, however, hydrogen storing capacity per weight is no match for demand of user, so this technology is not widely used yet. Therefore, that problem should be solved.