PURPOSE: To prevent the generation of bubbles due to entrapment or involvement of air, by performing feeding of a foamable synthetic resin stock liquid on the upper face of a filler layer linearly in parallel or in zigzag manner.

CONSTITUTION: A foamable synthetic resin stock liquid is delivered from a pouring device 22 on an upper face of a bottom face material 11 supplied continuously and filler 13 is sprayed almost uniformly on the upper face from a feeder 23. The foamable synthetic resin stock liquid 14 is supplied linearly in parallel or zigzag on an upper face side of filler 13 by the pouring device 24 and it is covered, then it is introduced into between a lower conveyer 25 and an upper conveyer 26, molded integrally into a predetermined thickness and a plate like foamed composite molded product 10 is obtained continuously.