A photothermographic element contains a non-photosensitive organic silver salt, a photosensitive silver halide which has been formed independent of the non-photosensitive organic silver salt, and a binder. An image forming layer contains the photosensitive silver halide, a latex of a polymer having a Tg of -30.degree. C. to 40.degree. C. as a main binder, and a compound of formula (I): ##STR1## wherein X is --N.dbd., --N(R)--, --0--, or --S--, wherein R is hydrogen, hydroxyl, aliphatic hydrocarbon, aryl or heterocyclic group, Z is a single bond or a group of atoms necessary to form a 5- to 7-membered ring with X, and Q.sub.1 and Q.sub.2 each are a group of atoms necessary to form an aromatic hydrocarbon or heterocyclic ring fused to the ring completed by Z.