PURPOSE: To manufacture a heat-sensitive diazo recording material which is excellent in heat responsiveness for a thermal head and in durability for long- time storage, by stabilizing a diazo compound with a mercapto compound or a sulfide compound.

CONSTITUTION: A solution containing a diazo compound which is commonly used for diazo photosensitive paper is stabilized by adding a mercapto compound or a sulfide compound in an amount 1W3mol times as much as that of the diazo compound. Also, a coupler such as phenol which is generally used and a heat-fusible or heat-softening substance for improving the quality of high-speed color formation are preferably used. Further, a water-soluble, or organic solvent-soluble or water-dispersed resin as a binder, and an acidic or basic substances as an auxiliary agent, a filler, etc. are added. By coating on a sheet of paper one or more layers of the mixture, a recording paper which can be installed and is excellent in heat responsiveness and durability for long-time storage can be obtained.