A vapor-phase growing unit of this invention includes: a reaction container in which a substrate is arranged, a first gas-introducing part having a first gas-introducing tube in which a gas-spouting port opening in the reaction container is formed, the first gas-introducing part serving to supply into the reaction container a first gas consisting of an organic-metal including gas, and a second gas-introducing part having a second gas-introducing tube in which a gas-spouting port opening in the reaction container is formed, the second gas-introducing part serving to supply into the reaction container a second gas which reacts with the organic-metal including gas and whose density is smaller than that of the organic-metal including gas. The gas-spouting port of the first gas-introducing tube and the gas-spouting port of the second gas-introducing tube are arranged along an outside periphery of the substrate arranged in the reaction container.