Provided is a method for fabricating a metal oxide thin film in which a metal oxide generated by a chemical reaction between a first reactant and a second reactant is deposited on the surface of a substrate as a thin film. The method involves introducing a first reactant containing a metal-organic compound into a reaction chamber including a substrate; and introducing a second reactant containing alcohol. Direct oxidation of a substrate or a deposition surface is suppressed by a reactant gas during the deposition process, as it uses alcohol vapor including no radical oxygen as a reactant gas for the deposition of a thin film. Also, since the thin film is deposited by the thermal decomposition, which is caused by the chemical reaction between the alcohol vapor and a precursor, the deposition rate is fast. Particularly, the deposition rate is also fast when a metal-organic complex with β-diketone ligands is used as a precursor. Further, a thin film with low leakage current can be obtained as the metal oxide thin film fabrication method using a chemical vapor deposition or atomic layer deposition method grows a thin film with fine microstructure.