PURPOSE: To prevent gas from remaining between a core material and a synthetic resin and to improve intimate and monolithic contact between them by a method wherein a metal film is formed by flame-spraying on the surface of the core material made up of wood and said core material is arranged in a molding die for injection molding.

CONSTITUTION: Wood is worked roughly and a metal like zinc, aluminum, etc. is flame-sprayed by means of the oxyhydrogen flame-spraying method or the like on the surface of the core material 2 on which locating stoppers are prepared at both ends 2a, 2b to form a metal coat 3. Subsequently said core material 2 is arrange in a cavity 11 of a molding die 10 and hot molten liquid resin 12 like ABS resin or the like is injected into the cavity 11. After it is cured and taken out of the die, both ends 2a, 2b of the core material 2 are cut off to obtain a molded body 1.