Contact-type scanning nonlinear dielectric microscopy (SNDM) can measure the distribution of linear and nonlinear dielectric properties of insulators with sub-nanometre resolution. SNDM, however, has a tip-abrasion problem, and this problem is one of the obstacles in obtaining a high-quality image. In this paper, in order to improve SNDM, we propose a non-contact scanning nonlinear dielectric microscopy (NC-SNDM) which focuses on the nonlinear dielectric signal for controlling the non-contact condition. With the NC-SNDM technique, topographic and SNDM images were obtained successfully. Moreover, from the calculation results, it was confirmed that NC-SNDM has atomic-order sensitivity to the gap between the tip and the specimen.