A heat-developable photographic material having improved preservability, which comprises a support having thereon at least one heat-developable photographic layer, said photographic material containing a dye represented by formula (I) ##STR1## wherein n and m each represents 0, 1, 2 or 3;p and q each represents 0 or 1;L represents a methine group or a substituted methine group;R.sub.1 and R.sub.2 are same or different and each represents an unsubstituted or substituted alkyl group;R.sub.3 and R.sub.4 are same or different and each represents a hydrogen atom, an alkyl group, an alkoxy group, a hydroxyl group, an unsubstituted or substituted amino group or a halogen atom; or said R.sub.3 and R.sub.4 form a condensed 6-membered ring;Z and Z' are same or different and each represents a non-metallic atomic group necessary for forming a substituted or unsubstituted 5-membered or 6-membered ring, or substituted or unsubstituted 5-membered or 6-membered ring which is condensed with another ring;X.sup..crclbar. represents an anion;r represents 1 or 2, and when the dye forms an internal salt, r is 1.