The present invention relates to fat composition, more specifically relates to 60% to 99.9% by weight of diglyceride containing 0.1 to 89.9% by weight of conjugated linoleic acid; 0.001% to 0.2% by weight of banaba extracts fermented by microorganism such as Bacillus sp. or Aspergillus sp.; and the balance being monoglyceride, triglyceride or a mixture thereof. The fat composition of the present invention comprises fermented banaba extracts as an antioxidant, and the fat composition excels in oxidation stability and keeping stability, therefore the fat composition of the present invention may be widely used as cooking oil.