An optical recording medium wherein a land and a groove are formed in both front and rear surfaces of a circular disk-like substrate respectively, at least a recording layer and a dielectric layer are formed on the surfaces of the substrate, and a hub is provided in only one of the surfaces and recording/reproducing are conducted by using a flying optical head, the optical recording medium being characterized in that in a state that the medium is supported by the hub so that the hub-attached surface directs downward, and in a region from the innermost periphery to L/3, where L is a distance from the innermost periphery to the outermost periphery of a recording/reproducing area, the center of curvature in a radial direction of that region exists at an opposite side with respect to the hub-attached surface of the optical recording medium, whereby the optical recording medium of high reliability wherein the distance between the flying optical head floating above the surface of the recording medium and the surface of the recording medium can be kept constant; uniform recording/reproducing signals can be obtained, and head crushing seldom occurs.