To provide an information processor capable of attaining the reduction in size and outward noise of the information processor at a low cost, and reducing the labor hour for the sorting in disposal or recycle of a circuit board.

This information processor comprises a vibration source 2 for generating noise mounted on the circuit board 4. The circuit board 4 is formed of a material having characteristics as a damping material. The circuit board 4 has a constraint plate 5 on the surface opposite to the mounting surface of the vibration source 2, and the noise is suppressed by a damping structure formed of two layers of the circuit board 4 and the constraint plate 5. As the material of the circuit board, a one having an elasticity of 10kgf/mm or less and a dynamic loss of 0.1 or more by tan δ value, preferably a one having an elasticity of 1kgf/mm or less and a dynamic loss of 0.5 or more by tan δ value is used. According to such a structure, the noise can be reduced with a simple structure without adding a new part.