With practical use of solar-energy-pumped laser, introduced in Chapter 2, and the laser smelting method, introduced in Chapter 3, the price of magnesium should fall markedly compared with what it is at present. The price is now 250–600 yen/kg, but it will not be difficult to bring it down to 100–150 yen range with the laser smelting method. I expect that the demand for magnesium as fuel source will rise rapidly in the market if its price falls to the range 100–150 yen/kg, and it will be competitive enough with gasoline.