Abstract: An improved structure of tool holding seat for a tool box or the like having a tool box cover enclosing an interior positioning board, a zipper formed along the edges of the box to provide zipping of the tool box is disclosed. The present invention is characterized in that a plurality of engaging members are provided on the top surface of the tool holding seat and the top surface of the engaging member is provided with a linear slot or a cross-shaped slot to form a flexible engaging element. A plurality of protruded dovetails are provided to detachably mount the tool holding seat onto the interior positioning board after the protruded dovetails pass through a corresponding circular pad and a corresponding circular hole provided on the tool holding seat, thereby a plurality of sleeves for wrench are inserted into the engaging members, which can be easily taken down for application, and the tool holding seat can be detachably replaced to accommodate the numbers and types of tools.