We have developed a hydraulic McKibben artificial muscle, which is small-sized and lightweight compared to other conventional actuators. In this paper, we have applied this muscle to a power robot hand. The hand fingers consist of metal links and muscles, and the contraction of the muscles generates the bending motion of the fingers. This hand has large holding capacity and shape adaptability to grasp objects. The experiments show that the maximum holding force of the hand is 4000N, and it can hold three types of different shaped objects; cylindrical objects having a diameter of φ267mm and φ165mm and a squire pole that is 200mm on a side. The hand has the potential for being applied to rescue robots in disaster areas and forestry industry, for example.