A thin film forming apparatus and a thin film forming method using the same are disclosed. In one aspect, the thin film forming apparatus comprises a mask that includes a blocking portion and an opening. It also includes an etching source that jets an etching gas through the opening of the mask to etch a thin film according to a pattern. The mask includes a gas blower for blowing a gas around the opening so that the etching gas does not penetrate into a thin film area corresponding to the block portion. When the thin film forming apparatus is used, a normal residual area of a thin film may be safely preserved and patterning may be accurately performed. Thus, the quality of a product manufactured by using the thin film forming apparatus may be improved.