In this paper, we propose a method to estimate position and orientation of objects for ring-type caging by visual sensor. Caging is a method to make an object inescapable from a region closed by rigid bodies such as a position-controlled robot hand. Ring-type caging is a type of caging in which a robot hand capture an object with holes, such as mugs, by grasping its handle part. Ring-type caging can be achieved by robots autonomously if the position and orientation of object, particularly that of its hole part, is retrieved. We show some experimental results that position and orientation of scissors are estimated.