Cooking utensil and manufacturing method therefor

A method of manufacturing a cooking utensil having outer and inner shells forming wall and bottom spaces between the outer and inner shells, the wall space being formed substantially along the height of the inner shell, wherein the wall and bottom spaces contain at least partially a heat conductive medium;

• and a heating coil arranged on the bottom of the outer shell for heating the outer shell of the cooking utensil, the method comprising the steps of:
• placing upright the outer shell on a concaved mold, the outer shell having a flange;
• placing a predetermined amount of the heat conductive medium into a space defined by the outer shell placed on the first mold;
• placing upright the inner shell in the outer shell so that the heat conductive medium at least partially surrounds the inner shell, the inner shell having a flange placed substantially parallel to the flange of the outer shell, wherein a convexed mold is placed in the inner shell to firmly hold the inner shell with respect to the outer shell;
• forming a rolled joint by curling together the flanges of the outer and inner shells a predetermined number of times to prevent the heat conductive medium from being discharged from the space even when the cooking utensil is exposed to heat, wherein the curling of the flanges of the outer and inner shells is carried out by placing at least one curling roller against the flanges while rotating the outer and inner shells with respect to the curling roller, wherein after the flanges of the outer and inner shells are curled for at least four times, the curling roller is pressed against at least one of the concaved and convexed molds to flatten the rolled joint.