PROBLEM TO BE SOLVED: To provide a freshness-keeping method enabling favorable preservation of freshness of fresh food, real flowers and the like: and to provide a freshness-keeping device enabling favorable preservation of freshness of fresh food, real flowers and the like. SOLUTION: The freshness-keeping method comprises the following process: applying high voltage (5, 10, 12 kV) via a direct-current power source 31 between an acicular electrode 33 and a flat-plate electrode 32 in the air to perform static discharge so as to generate oxides of nitrogen; and introducing the oxides of nitrogen into a storage warehouse to maintain freshness of the fresh food in the storage warehouse. The freshness-keeping agent is obtained by arranging extra-pure water in an electric field to make a nitrogen compound such as NO3-N, NO2-N or NH4+-N dissolve in water. The freshness-keeping agent is applied, sprayed or atomized to the fresh food to keep the freshness of the fresh food. COPYRIGHT: (C)2007,JPO&INPIT
