To provide a freshness preserving method capable of appropriately preserving freshness of farm crops after harvesting and improving visibility of farm crops.SOLUTION: A freshness preserving method of the present invention is a freshness preserving method in which an irradiation light is irradiated onto farm crops after harvesting. An irradiation light having a peak in a wavelength range of 700-1000 nm is irradiated under the presence of a white light. Irradiation periods are a main irradiation period for 10 minutes or more in which an irradiation light is irradiated, and a secondary irradiation period for 10 minutes or more in which an irradiation light is irradiated by the irradiation intensity of 50% or less of an average irradiation intensity of the immediately preceding main irradiation period, or the irradiation light is not irradiated. When the main irradiation period is X hours, the secondary irradiation period is Y hours, and the repetition frequency of the main irradiation period per day is Z times, the relationships of 0.16≤X≤12, X≤Y, and 1≤Z≤72 are satisfied.SELECTED DRAWING: Figure 1【課題】収穫後の農作物の鮮度を適切に保持でき、且つ、農作物の視認性を向上できる、鮮度保持方法を提供する。【解決手段】鮮度保持方法は、収穫後の農作物に照射光を照射する鮮度保持方法であって、白色光の存在下において、700nm以上1000nm以下の波長範囲にピークを有する照射光を照射する。そして、照射光が照射される10分以上の主照射期間と、直前の前記主照射期間の平均照射照度の50%以下の照射照度で照射し或いは前記照射光を照射しない10分以上の副照射期間と、がある。主照射期間がX時間であり、副照射期間がY時間であり、1日あたりの主照射期間の繰り返し回数がZ回である場合、0.16≦X≦12、且つ、X≦Y、且つ、1≦Z≦72の関係を満たす。【選択図】図1