The present invention relates to a pharmaceutical composition for the prevention or treatment of diabetes or fatty liver comprising a CYP4A (cytochrome P450A) inhibitor as an active ingredient. The compound of the present invention has activities of promoting glucose uptake into hepatocytes, inhibiting fat accumulation in liver cells, and inhibiting reactive oxygen production in mitochondria, and thus can be very usefully used for the development of a therapeutic agent for diabetes or fatty liver.