An etching method is disclosed. The etching method includes the steps of: preparing a substrate 5; forming first and second films 61, 62 each having predetermined internal stress on the substrate so that the internal stresses of the first and second films 61, 62 are canceled out or reduced with each other; forming a plurality of initial holes 63 in the first and second films 61, 62 to form a mask 6; and forming a plurality of concave portions 3 in the substrate 5 at portions corresponding to the plurality of initial holes 63 by subjecting the substrate 5 to an etching process using the mask 6.