In the invention, there are included a first image generating that generates image data corresponding to a shape data of a machining target as machining target image data, a second image generating that generates, based on NC programs created in the past, image data of a machining finish shape as finish shape image data, a storing that stores the finish shape image data associating with an NC program corresponding thereto, a similarity calculating that compares the machining target image data and the finish shape image data to calculate similarity of both the image data, a searching that searches, based on the similarity, candidates of finish shape image data similar to or matching the machining target image data and displays the candidates, and a first program displaying that displays, out of the candidates of the finish shape image data, an NC program for designated finish shape image data.