A reversibly changeable heat-sensitive recording medium comprising a heat-sensitive layer which comprises a support, and a resin matrix and a low molecular weight organic material dispersed inside the resin matrix, the transparency of which changes reversibly depending on the temperature and which is formed on a support, and, if necessary, including a protection layer or an intermediate layer prepared above the heat-sensitive layer or on the lower surface of the support layer or between the support layer and any other layer or between any other layers in the reversibly changeable heat-sensitive recording medium, characterized in that a fluorescent body which emits visible light through the excitement by visible light is included in at least a portion of the support body, heat-sensitive layer and, if necessary, any other layer. This medium has excellent visibility and can be used with backgrounds of any of many possible colors.