A removable flame heat regulating apparatus for a cooktop of a gas stove including an inner hollow shell and outer wall which are both placed onto the cooktop to surround an upper section of a gas burner wherein the outer wall surrounds the inner hollow shell. The inner hollow shell is circularly arcuate in shape, and has a smaller bottom opening with a smaller bottom edge and a larger top opening with a larger top edge. A plurality of air passages of openings penetrate through lower and upper parts of the inner hollow shell, wherein the air passages are more densely located in the lower part as compared with the air passages which are less densely located in the upper part. The outer wall has a plurality of air passages of openings which are evenly penetrate therethrough. In addition, a plurality of extensions projecting upwardly are spaced apart onto a top edge of the outer wall to support a cookware. The apparatus improves the heating efficiency of a flame of the gas burner and prevents undesirable heating of a handle of the cookware in cooking.