An object of the present invention is to provide a thermal recording material which is excellent in all of the following characteristics: plasticizer resistance, image stability against moisture and heat, the resistance to background fogging under moisture and heat, and the retention of color developing ability. Provided is a thermal recording material having, on a paper support, a heat-sensitive recording layer containing a colorless or light-colored dye precursor and a developer which reacts with the dye precursor on heating and converts the dye precursor to its colored form, the paper support containing 0.25 to 1.0% by mass of a neutral rosin sizing agent relative to the pulp solid content in combination with calcium carbonate and aluminum sulfate, the developer having a phenylureido moiety in its molecule.