PURPOSE: To provide a composite panel which facilitates working, is capable of reducing a production cost and has soundproofing, vibration damping and heat insulating characteristics.

CONSTITUTION: The first surface plate 11 of a pair of the surface plates 11, 12 facing each other is provided with reinforcing ribs 13 projecting toward the other second surface plate 12. Recessed parts 14 and projecting parts 15 fitting each other are formed at the front ends of these reinforcing ribs 13 and the parts of the second surface plate 12 facing the reinforcing ribs 13. The recessed parts 14 and the projecting parts 15 are adhered and joined to each other by interposing adhesives 16 having strength and proper elasticity therebetween. As a result, the assembled composite panel 10 is capable of satisfying all of the soundproofing, vibration damping and heat insulating characteristics, facilitating working and reducing the production cost.