A vapor deposition apparatus for forming a deposition layer on a substrate includes a supply unit that is supplied with a first raw gas to form the deposition layer and an auxiliary gas, wherein the auxiliary gas does not constitute a raw material to form the deposition layer, a reaction space that is connected to the supply unit to be supplied with the first raw gas and the auxiliary gas, a plasma generator in the reaction space to convert at least a portion of the first raw gas into a radical form, and a first injection portion that is connected to the reaction space and that supplies at least a radical material of the first raw gas toward the substrate.