The present invention relates to a brake fluid composition comprising (a) a glycol compound and boron-containing compound mixture as solvents, (b) corrosion inhibitior, (c) and tartatric acid, imidazole or a mixture of tartaric acid and imidazole as antioxidants. Provided is a brake fluid composition having improved capabilities for inhibiting thermal oxidation, metallic and high-temperature corrosion. The brake fluid composition according to the present invention significantly improves long-term durability by reducing metal dot corrosion and preventing boronic acid precipitation on a test piece, while having a superior thermal oxidation inhibition capability, and has superior capabilities for inhibiting high-temperature oxidation and corrosion while having negligible effects on the equilibrium reflux boiling point and the wet equilibrium reflux boiling point.