The present invention relates to a flat rack container, and more particularly, to an integral buffering apparatus disposed between end walls and a base and for automatically controlling a flow rate of oil that flows in a cylinder housing through channels formed in a slider when the end walls are folded, to control a falling speed of the end walls, thereby absorbing an impact of the end walls, preventing damage of the end walls and the base, and ensuring safety of workers. The integral buffering apparatus includes a cylinder housing including a space for accommodating oil; a slider disposed in the space to be movable in a length direction of the cylinder housing and to divide the space into a first space and a second space; first oil channels and a second oil channel for connecting the first space and the second space to each other.