Abstract: A heat-sensitive recording medium comprising, on a support, a heat-sensitive color-developing layer containing a colorless or light-colored leuco dye (or an electron-donating dye precursor) and a color-developing agent (or an electron-accepting substance) reacting with the leuco dye to develop color as main constituents, said leuco dye being a compound represented by the formula (I): ##STR1## wherein X represents CH.sub.3 --(CH.sub.2).sub.3 --CH.sub.2 or CH.sub.3 --CH.sub.2 --CH.sub.2 and Y represents CH.sub.3 --(CH.sub.2).sub.3 --Ch.sub.2 or CH.sub.3, and said heat-sensitive color-developing layer containing at least one of the compounds represented by the general formula (II) and (III): ##STR2## where R.sub.1, R.sub.1 ' are respectively any one of H, Cl, and CH.sub.3, and may be the same with or different from each other: ##STR3## where R.sub.2, R.sub.2 ' are respectively any one of H and CH.sub.3, and may be the same with or different from each other.