Recently, some kinds of laser machines have often been used for a special machining. Generally, it has been thought that static stiffness is unnecessary for these machines, because laser machining never generate relative machining force between a laser torch and a work, and the laser elements are very light. Therefore, dynamic stiffness in these machines also became low, and waiting time after the movement of the table is long. Hence, some countermeasures of the structural vibration are necessary for improving availability of the laser machine. In this paper, a vibration countermeasure has been proposed. At first, vibration properties of conventional laser machine was investigated using FEM simulation. Next, damping ratio of the structure was improved by the powder composite damper. It is concluded from the results that ; (1) The number of natural frequency on low frequency territory decreased and the compliance became small. (2) The logarithmic decrement of the structure became big.