The present invention relates to a tool cabinet including an upper cover, a bottom board, a case body and a shelf accessory. The case body includes rotatably interconnected case boards, which are foldable with each other. The upper cover and the bottom board are loosely rabbeted into the case body. Without disconnecting each case board, each case board can be folded only by pulling out the pin in the upper cover, turning over the upper cover, then taking out the shelf and the upright column, releasing the block rabbeting, and folding the case boards. It is done after the shelf and the upright column are placed into a predetermined space of the right board and back board during the folding process. It is very simple and convenient. Hence, it is convenient to carry the tool cabinet after it is folded.