A film-like heater which has a graphite film made of a polymer film baked at a temperature higher than 2,000 .degree. C. and having a good thermal conductivity, a good flexibility and a good resistance to high temperature, so that it is applicable to a thin face heat-retaining or heating means having various designs such as a seat heater fittable to a body shape, a vapor deposition boat operable at a high temperature and a compact heating device or apparatus.