Disclosed is a photothermographic material comprising on support a light-insensitive silver salt of an aliphatic carboxylic acid, a light-sensitive silver halide and a reducing agent for silver ions, wherein the photothermographic material further comprises a copolymer comprising a backbone comprising a chain having a monomeric repeating unit, represented by formula (1) and a chain having a monomeric repeating unit, represented by formula (2). ##STR00001##