A sawing machine having a spindle and circular saws thereon adapted to rotate with and axially slidably mounted on the spindle. A movable joint member or a one-way clutch is provided between the spindle and the saws. While the spindle is rotating at a low speed or is at a stop, the joint member or the clutch is in its inoperative position, keeping the saws disengaged from the spindle so that the distances between the adjacent saws can be adjusted freely. When the spindle begins to rotate at a high speed, the joint member is moved outwardly or the clutch is engaged by centrifugal force, thus locking the circular saws to the spindle.
