To provide a method for manufacturing a lens by which the surface roughness produced on the machined face can be improved.

In the method for manufacturing a lens, the surface of a lens base body is machined with a ultra-precision lathe and a transparent thin film is formed on the obtained machined surface to improve the maximum height P-V to ≤0.04 μm. The thin film consists of an organic silicon compound expressed by general formula (I): R1aSi(OR2)4-a or its hydrolyzed composition and metal oxide fine particles. In formula (I), each of R1 and R2 is independently an alkyl group, aryl group, epoxy group, methacryloxy group, glycidoxy group or amino group and a is an integer 0 to 2.