A holding device including an object to be held by the holding device and having six first flat surfaces, a holding member having six second flat surfaces each being opposed to and parallel to a corresponding one of the first flat surfaces, wherein the holding member has three holding portions of one of a protruded shape and a recessed shape, and wherein two of the second flat surfaces define at least a portion of the protruded shape or recessed shape of the holding portions, and rolling elements each being provided between associated ones of the first and second flat surfaces. The object is supported by the holding member through the rolling elements.