Gravitational wave is a one of the important predictions of general relativity that describes gravity as a distortion of the space-time. A direct measurement of gravitational wave from astronomical sources is expected with recent upgrading and constructing detectors: advanced LIGO in US, advanced Virgo in Europe and KAGRA in Japan. Measurement of gravitational waves will be important tests of general relativity in strong gravity field, comparing with past tests in weak gravity of solar system. On the other hand, typical gravitational wave sources are massive, compact and drastic astronomical events such as supernovae, coalescence of binary neutron stars or black holes. Due to very weak coupling of gravity, gravitational waves carry out information from deep inside a source. Moreover, such a drastic astronomical events may appear in counterpart observations by optical, X- or Gamma-ray, neutrino, etc.

The author is presently working for the construction of KAGRA, and starting the Grant-in-Aid project “New Developments in Astrophysics Through Multi-Messenger Observations of Gravitational Wave Sources”. We well introduce a fundamental technique and status of the gravitational wave detectors briefly, and display the prospects of scientific outcome of gravitational wave sources in near future detections.