PURPOSE: To provide a reversible thermal recording body which does not cause deterioration of image irregurality or coloring properties or achromatizing properties based on aggregation of particles of coloring agent or developer scattered in a resin matrix to be produced by repeating formation or erasure of an image.

CONSTITUTION: In a reversible thermal recording medium provided with a recording layer containing an electron-donating coloring agent and electron-accepting developer scattered in a resin matrix, a colored and recorded state is formed by heating and melting and an achromatic state from which a record is eliminated by heating at a lower temperature than a coloring temperature, mean particle diameters each of the electron-donating coloring agent and electron-accepting developer scattered within the resin matrix are made into 1μm or less.