The Large Hadron Collider (LHC) is now under construction at CERN, Geveva, to study frontier researches of particle physics. The LHC is the biggest superconducting accelerator using the most advanced cryogenics and applied superconductivities. The accelerator and large scale detectors for particle physics experiments are being constructed by collaboration with European countries and also by participation with non-CERN countries worldwide. In 1995, the Japanese government decided to take on a share in the LHC project with funding and technological contributions. KEK contributes to the development of low beta insertion superconducting quadrupole magnets and of components of the ATLAS detector by collaboration with university groups. Some Japanese companies have received contracts for technically key elements such as superconducting cable, cold compressor, nonmagnetic steel, polyimide film, and so on. An outline of the LHC project and Japanese contributions are described.