The present invention relates to an anti-theft toolbox comprising a lower frame, an upper frame and a locking element. The lower frame and the upper frame latch together by locking portions. The locking portions have notches. The locking element has two tighten masses with a groove spanned across them. The inner wall of the groove has opposite flanges. The flanges are anchored into the corresponding notches. The two tighten masses are bound by a plurality of binding portions which has a hollow in-between every two adjacent binding portions.