A positioning apparatus for a foldable running machine includes a base, a running platform, and a folding assembly. The running platform is pivotally connected to the base. The folding assembly is connected to the running platform and includes at least one slide guide rail, at least one cylinder, and at least one rod. The cylinder is slidably coupled to the slide guide rail, wherein both the cylinder and the slide guide rail are parallel to the extending direction of the running platform. The rod is pivotally connected to the cylinder and pivotally connected to the base.