A pressure source material is loaded into a space having constraint device 1, which is formed partly by optically transparent material 1a, 1b, and is disrupted under volume constraint. Light energy is externally supplied to the pressure source material constrained in the space through the optically transparent material by employing the device to apply light energy. The disruption of atomic bonds in the pressure source material is induced by heating the pressure source material above the boiling point thereof through the supplied energy. Exceptionally high pressures are generated in the space by the use of expansive forces arising from the disruption of atomic bonds. Such a configuration can implement ultrahigh pressure abilities that has not been achieved, so far.