The detection of gravitational waves will reveal new aspects of the Universe that cannot be observed by other means, such as the details of the primordial cosmos, the core dynamics of the supernovae, and the surface behavior of black holes. For the purpose of opening a new window, we are promoting the KAGRA project together with ICRR, KEK, and other universities. KAGRA is a large cryogenic gravitational wave antenna using a 3 km laser interferometer placed in the Kamioka underground site. TAMA300, the 300-m laser interferometer situated on Mitaka campus, is a prototype of KAGRA and acts as a test facility to evaluate key elements and techniques before installation on KAGRA. The project office is also promoting the DECi-hertz Interferometer Gravitational wave Observatory (DECIGO) in space in anticipation of the future development.