The great interest in photochromic materials for high-density optical memory has been increased for the past decade. A super-low power readout method has been proposed to solve a problem about degradation of recorded information by readout process. About 106-time readout was demonstrated by the method. New high-density optical memory, a super-resolution disk with a photochromic mask layer, was introduced. The super-resolution method has enabled us to increase the recording density of conventional optical disks. Ultra-high density near-field photochromic memory as a new innovative storage technology was also discussed.