To obtain a composite body of artificial marble with a foamed body, which is lightweight and excellent in appearance.

This composite body is a foamed body having the artificial marble in the surface layer and the foamed body in its inside layer and is obtained by charging the foamed body having fine pores on the surface into a syrup for the artificial marble containing an inorganic filler and a polymerization initiator and polymerizing by heating, and the surface layer and the inside layer are rigidly adhered with each other since the artificial marble exists in the fine pores of the foamed body in the boundary between the surface layer and the inside layer.