PURPOSE: To provide a composite damping metal plate which improves the strength and flexural rigidity of a main plate and is super-light-weight without reducing damping property.

CONSTITUTION: This is a composite damping metal plate 11 which nips both faces of a main plate 12 by auxiliary plates 13 and connects these main plate 12 and auxiliary plates 13 partially. The main plate 12 is in the shape of waves or recessed and protruded parts like hat in the longitudinal direction or in the lateral direction or in the shape of recessed and protruded parts like hat in the longitudinal direction and in the lateral direction.