Thermal transfer sheet

A thermal transfer sheet comprising a back face layer provided on one surface of a substrate and a transfer layer provided on the other surface of the substrate, wherein

• the transfer layer has a single-layer structure or a layered structure comprising a protective layer,
• the back face layer contains a resin component including Si in a structure, and
• when the thermal transfer sheet is cut out to a size of 30 mm×230 mm, both ends in 5 mm of the 230 mm width of the cut-out thermal transfer sheet are fixed on a fixing table, and a rubbing test is conducted, in which test, a white cotton cloth for friction impregnated with methyl ethyl ketone, with a load of 1.96 N applied thereon, is reciprocated 100 times at a rate of 30 reciprocations per minute on a 30 mm×220 mm area of the back face layer of the fixed thermal transfer sheet in a 220 mm width direction, a mass reduction ratio represented by the following equation is 1% or less.
• Mass reduction ratio (%)=((mass of thermal transfer sheet before rubbing test−mass of thermal transfer sheet after rubbing test)/mass of thermal transfer sheet before rubbing test))×100 Equation (1)