PURPOSE: To obtain satisfactory heat-resistance and molding, by using a resin compound composed of a specific polybuthylene tere phtalate resin and a specific inorganic filler mixed with the resin.

CONSTITUTION: A food vessel for cooking by a microwave oven is made by injection molding of an a resin compound of polybuthylene tere phtalate resin with a melt index of 30-150 measured in the condition of 235°C, 2150g load according to ASTM D-1238, mixed with 10-55% by weight (against the whole compound) of one or more inorganic fillers selected from talc and calcium carbonate. Polybuthylene tere phtalate is obtained by the polymerization of 1,4-butanediole and terephthalic acid or its lower alcohol ester. The inorganic filler has a remarkable effect on reducing electroinductive loss. The thick molding obtained in this way has a good molding workability, a high deforming temperature, a durability against cooking in a microwave oven, and a great strength.