An intelligent vibration gripper has been developed. The gripper can handle an object of unknown weight and unknown surface conditions with the most suitable grasping force. Additionally, the gripper can adapt the grasping force to the most suitable value for the object even if the weight and the surface conditions of the object change. The gripper has two parallel fingers. Each finger is composed of a mechanical vibration system with two mass blocks and two springs. In one mass block, a harmonic force is always generated and is absorbed by a dynamic damper consisting of another mass block and a spring, so that one mass block is kept in a stationary condition. The object is grasped by stationary blocks on both sides. When the object is grasped with the most suitable grasping force, the object and all of the mass blocks become stationary because harmonic forces are transmitted to the object and the two harmonic forces cancel out each other. In this gripper, the grasping force is adjusted to the most suitable values by detecting the amplitudes of the dynamic dampers. This paper describes a fundamental principle of a new vibration gripper.