A bone fusion device includes a main body and a movable frame. The main body has an accommodation hole. A top surface and a bottom surface of the main body are provided with a plurality of first teeth. The movable frame is located in the accommodation hole. The movable frame has a through hole longitudinally penetrating a first surface and a second surface thereof. A first end of the movable frame is fixed to the front end of the main body, and a second end is suspended relative to the rear end of the main body. The first surface and the second surface are provided with a plurality of second teeth. The movable frame is transversely formed with a groove to define an upper portion and a lower portion, enabling the upper portion and the lower portion to be elastically expanded with the first end as a fulcrum.
