This invention discloses a manufacturing method of a heat sensitive material having a transparent heat sensitive layer comprised of controlling transparency of heat sensitive layer by coating a composition containing an emulsified dispersion prepared by dispersing a color developer dissolved into an organic solvent slightly soluble or insoluble in water and microcapsules containing at least a colorless or light colored electron donating dye precursor (core material) and then drying the coat, in which a refractive index of the core material and that of an oil phase of the color developer dispersion are properly adjusted. When providing a transparent heat sensitive layer obtained by the above method on a printed support, a printed matter can be seen through the heat sensitive layer.