In a method for forming micro lenses, a lens material layer made of an inorganic material is formed on a substrate, and an intermediate layer made of an organic material is formed on the lens material layer. Then, a mask layer made of an organic material is formed on the intermediate layer, and lens shapes are formed in the mask layer. The lens shapes of the mask layer are transcribed to the intermediate layer by etching the mask layer and the intermediate layer. Thereafter, the lens shapes of the intermediate layer are transcribed to the lens material layer to form micro lenses by etching the intermediate layer and the lens material layer using a processing gas containing SF6 gas and CHF3 gas.