A reversible thermosensitive recording medium including a substrate; and a reversible thermosensitive recording layer located on the substrate and reversibly achieving a relatively colored state and a relatively discolored state depending on the temperature to which the recording layer is heated or the cooling speed at which the recording layer is cooled after heating, wherein the reversible thermosensitive recording layer comprises a polyalkylene glycol compound having a number average molecular weight not less than 2,000 exclusive of polypropylene glycol having a number average molecular weight not greater than 5,000. A reversible thermosensitive recording device, and an image processing method and apparatus using the reversible thermosensitive recording medium are also be provided.