A neutron has dual nature of a wave with a wave length of about 1 Å and a particle with a kinetic energy of about 100 meV. A neutron also has excellent transparency of matter and a nuclear magnetic moment. Owing to these properties, neutron scattering is a powerful method to investigate the structure and dynamics of atoms and electron spins in condensed matter. Since 1993, Neutron Science Laboratory (NSL) has been playing a central role in neutron scattering activities in Japan not only by performing its own research but also by providing a general user program using the university-owned 12 neutron scattering spectrometers installed at the research reactor JRR-3 (20 MW), JAEA (Tokai, Ibaraki). Furthermore, NSL owns a cutting-edge inelastic neutron scattering spectrometer HRC in J-PARC, which started its operation in 2009 and has been managed with KEK. Major research areas supported by the NSL user program are solid state physics (superconductors, topological materials, novel quantum phases, etc.), soft matter (polymers, gels, etc.), complex systems (glass, liquid, clathrate materials, etc.), material science (ionic conductors, hydrogen systems, etc.), biological physics, and fundamental physics on neutrons. The NSL also operates the US-Japan cooperative program on neutron scattering since 1984.