A showerhead for chemical vapor deposition includes: a plurality of reactive gas showerhead modules separated each other and having the same number as the number of kinds of reactive gases injected from the showerhead, each having a mixing zone in the reactive gas showerhead module to induce a mixing of a reactive gas and an injection support gas used to regulate the injection velocity of the reactive gas and a plurality of reactive gas injection tubes connected to the bottom surface of the reactive gas showerhead module for injecting the reactive gas mixed with the injection support gas over the substrate; and a purge gas showerhead module mounted under the reactive gas showerhead modules, with a purge gas supply port for supplying a purge gas to the purge gas showerhead module.