THERMAL RECORDING MEDIUM

PURPOSE: To obtain a thermal recording medium having excellent reading suitability in a near infrared region and excellent preservability by using fluoran compound represented by a specific formula as leuco dye, and forming pigment in an intermediate layer as a hollow particle in the medium utilizing the color developing reaction of the leuco dye with coloring agent. CONSTITUTION: In the thermal recording medium comprising an intermediate layer containing pigment and adhesive, a thermal recording layer containing leuco dye and coloring agent and a protective layer sequentially provided on a support, as the leuco dye, fluoran compound represented by a formula is used, and the intermediate layer contains hollow particles as the pigment. In the formula, R1 , R2 are 1-6C alkyl group, and R3 , R4 are hydrogen atom or 1-6C alkyl group. As the leuco dye, preferably 3-p-dimethylaminophenylamido-5,7- dimethylfluoran is used. As the hollow particle contained as the pigment in the intermediate layer, spherical hollow particle or foamable filler is used.