The invention is a novel developer composition which comprises one or more phenol derivative of sulfonamide structure represented by the formula (1) and one or more constituents selected from a polyvalent metal compound, antioxidant and reducing agent and provides dispersion having excellent preservation stability on atomization in water. The heat sensitive recording material comprising the developer composition has high color density in developed image and is also excellent in whiteness degree before recording. ##STR1## wherein X.sub.1 is a hydrogen or halogen atom, an alkyl, alkoxy or hydroxyl group, Z.sub.1 is a hydrogen atom or alkyl group, and R.sub.1 is an unsubstituted or substituted alkyl or aryl group.