Germanane (GeH) is an attractive layered material with potential applications in channel of field-effect transistors and can be topochemically synthesized from CaGe2. So far, the film growth method of CaGe2 has been limited to molecular beam epitaxy. In this study, we demonstrate CaGe2 epitaxial film growth on Ge(111) substrates at 675–800 °C by a scalable close-spaced evaporation method using a conventional lamp annealing furnace. Detailed investigation of the film structure by X-ray diffraction reveals that the CaGe2 films consist mainly of the metastable 2H polytype and of a minor amount of the stable 6R polytype. The CaGe2 film deposited at 800 °C is converted to GeH by low temperature HCl treatment while the other CaGe2 films transform to crystalline and nanocrystalline Ge. The reasons why only the CaGe2 film synthesized at 800 °C is converted to GeH is discussed in terms of the film microstructure observed by scanning electron microscopy. The absence of GeH in low-temperature deposited films after HCl treatment is attributed to the exfoliation of island crystals during HCl treatment. We thus show that close-spaced evaporation is a rapid and scalable method to prepare CaGe2 epitaxial films as a precursor of GeH films and that the roughness of CaGe2 should be improved for efficient conversion to GeH.