Abstract: A front body structure of a vehicle capable of controlling a crashed mode of a front side frame at a collision with reduced weight. A rear frame of the front side frame has high rigidity by making the thickness thereof thicker than that of the front frame. The weight of the front body is reduced by lessening the thickness of the front frame. A crashed mode is controlled by adjusting the thickness of the front frame and the rear frame. The front and rear frames are joined by a butt joint to each other at a set angle with respect to a vertical direction of a car body, so that a joint part between both frames can be easily bent at a collision. A reinforcement and a engine mount are respectively disposed at the inside and the outside of the joint part to reinforce the joint part.