When referred to standard conditions, 1 m3 solid hydrate contains up to 200 m3 of natural gas, depending on the pressure and temperature. Such a large volume of natural gas hydrate can be utilized to store and transport a large quantity of natural gas in a stable condition. In the present investigation, experiments were performed to investigate how the formation of natural gas hydrate is governed by such factors as the pressure, temperature, and gas composition. The results indicate that if the subcooling of structure Ⅱ is more than 11 K, a hydrate is rapidly formed. In addition, we found that a pressure increase was more advantageous than a temperature decrease at effecting an increase in the gas consumption.