PURPOSE: To provide a thermal transfer sheet easy to produce coloring matter and obtaining recorded matter high in color density, excellent in light fastness and having a sharp yellow-orange hue.

CONSTITUTION: A thermal transfer sheet has a colorant layer to which one or more kind of pyridone dis-azo coloring matter represented by formula [1] (A is a phenyl group and R is a hydrogen atom, an alkyl group or a phenyl group) is added,. The colorant layer is formed by coating a base film being a base material with ink prepared by dissolving the above-mentioned coloring matter in a medium along with a binder or dispersing the same in the medium in a fine granular form along with the binder and drying the coated film. As the binder, a water-soluble resin such as a cellulosic resin and a resin soluble in an org. solvent such as an acrylic resin are used and, as the base film, a polyethylene terephthalate film is excellent from the aspect of mechanical strength, solvent resistance or economical efficiency.