PURPOSE: To produce a thermal recording material having small contents of a metal ion and a halogen ion not corroding the metal part of a thermal head and having only slight coloration of its background by performing ion exchange treatment using a cation exchange resin and an anion exchange resin at the time of the completion of the microencapsulation of a microcapsule and/or at the time of the completion of the emulsification and dispersion of an emulsified dispersion.

CONSTITUTION: A microcapsule solution containing microcapsules obtained by microencapsulating one of a colorless color forming component A and a colorless color forming component B forming a color upon the reaction with the color forming component A at the time of heating is mixed with an emulsified dispersion prepared by mixing the non-microencapsulated color forming component with an aqueous solution containing a water-soluble polymer and a surfactant as a solid dispersion or as an aqueous solution obtained by dissolving the non-encapsulated color forming component in an org. solvent hardly soluble or insoluble in water under stirring to prepare a coating solution which is, in turn, applied to a support. At the time of the completion of microencapsulation and/or at the time of the completion of the emulsification and dispersion, ion exchange treatment is performed using cation and anion exchange resins.