Preshaping is an important issue for a robot hand to grasp a moving object successfully. Generally, a moving object in 3D space has rotational motion as well as translational one. This study discusses dynamic preshaping issue for such an object changing the posture momentarily. In this paper, we focus on determining the timing for grasping the object. We first show a strategy to extract candidates of timing for grasping. We also verify the proposed strategy by experiments using a high speed hand with the assistance of a high speed vision.