Abstract: As it has been described above, a color developing agent composition according to the invention, which includes a compound given by Formula (I) ##STR1## wherein R.sub.1 through R.sub.6 are substituents respectively and independently are selected from the group consisting of a hydrogen atom or any substituted or unsubstituted group selected from among an alkyl group, an alkoxyl group, a hydroxyl group and an amino group, possible substitution groups for the selected group comprising a hydroxyl group, an amino group and an alkoxyl group; (2) a paraphenylene diamine type color developing agent; and (3) a compound given by Formula (II) ##STR2## wherein R.sub.7 and R.sub.8 are substituents respectively and independently selected from the group consisting of a hydrogen atom or a substituted or an unsubstituted alkyl group.