  We develop a framework for the reconstruction of the bulk theory dual to
conformal field theory (CFT) without any assumption by means of a flow
equation. To this end we investigate a minimal extension of the free flow
equation and find that at a special parametrization the conformal
transformation for a normalized smeared operator exactly becomes the isometry
of anti-de Sitter space (AdS). By employing this special flow equation to
O$(N)$ vector models, we explicitly show that the AdS geometry as well as the
scalar field satisfying the GKP-Witten relation concurrently emerge in this
framework.
