To produce a high-quality molded article containing increased amount of a food waste as an additive.

A thermoplastic resin is mixed with a water-containing food waste and molded to a prescribed form. The molding process comprises the first forming step to preform a mixture of the food waste and the plastic material, a degassing step to press the preformed plastic material under heating and remove the contained gaseous component and the second forming step to form the degassed material to a prescribed form.