Recently, micro fabrication technology has been attracting attention. In particular, methods that can be used to fabricate microelectromechanical systems (MEMS) and microscopic optical devices, such as photonic crystals, are in huge demand. In this study, we propose a nano-stereolithography method that employs evanescent light instead of propagating light, which allows us to achieve 100-nanometer-level accuracy. The nano-stereolithography method builds 3-dimensional microstructures by curing photosensitive resin in a layer-by-layer fashion. We have had some problems in lateral shape control of a single layer, and dissolved oxygen in resin is estimated to cause the problems. In this report, we focused on a single layer, and substantially improved lateral shape control by nitrogen purge.