Caging is a method to make an object inescapable from a cage composed of a robot bodies. Although caging has merits, it is seldomly used in factories. This is partly because we do not understand the form of robot hands suitable for caging. In this paper, we consider hand designs for 3D caging. We examined the usability of several hand designs by executing caging tasks with hands we built. Then we proposed hands for 3D caging based on the usability experiments.