Abstract: A vacuum evaporation apparatus for depositing an evaporant as a thin film on a substrate comprises a sealed container including a substrate support for mounting thereon the substrate. A heat medium such as of diphenyl, for example, is filled in the substrate support. The heat medium in the substrate support is supplied with heat by a heater. When heated, the heat medium is vaporized and the vapor gas having absorbed heat of evaporation is moved quickly from a high-temperature region to a low-temperature region. The vapor gas in the low-temperature region is supersaturated and turned into the heat medium liquid. The heat energy born as latent heat by the vapor gas is given off to heat the substrate support uniformly. With this thermosiphon action, the substrate can be heated through the substrate support so as to have a uniform overall temperature distribution for forming a uniformly deposited thin film on the substrate surface.