The national project of methane hydrate development in Japan (MH21) started in 2001 and has made a great progress in these years. In the project operated by MH21 research consortium, we have carried out extensive experimental and computational R&D on modeling and production method for methane hydrates. Fundamentals for the properties of hydrate-bearing sediments and the changes in production process have been investigated using artificial samples and core samples from ocean survey. Thermal, mechanical and geochemical properties have been analyzed and compiled as a database. The dissociation behaviors of hydrate samples have been observed in practical conditions and for production methods. The original simulator for methane hydrate production is also developing for assessing the MH production.