PURPOSE: To provide a cooking container for a microwave heater in which uniform heating free from unevenness is achieved and a uniform convection current and a large number of hot spots are generated in the container and uniform vapor pressure is maintained and excessive water vapor is smoothly discharged, and sealing and easily unsealing characteristics can be ensured.

CONSTITUTION: A container body 2 comprises a molded item formed from polypropylene or the like and has an integral construction in which its horizontal cross sction has an elliptically oblong shape and an inner bottom has an approximately flat bowl shape and the thickness of a bottom 5 is larger than that of a side wall 4 and the thickness increases continuously from the side wall 4 toward the bottom 5. And a cover body 3 is a two-colored molded item comprising a body portion 7 made of polypropylene or the like and a peripheral fitting portion 8 made of elastomer. And a pressure regulating valve mechanism consiting of an opening 14 as a vapor release hole and a thin plate valve 16 with an angle 15 is provided in the cover body 3.