A board anchor comprising a screw shaft, freely rotating anchor section attached to the screw shaft via a spring and stop attachment for re-positioning the anchor section in a crosswise position against the screw shaft from a position parallel with the screw shaft, a stopper mechanism that stops the above screw shaft in the above cross position, and an attachment ring that screws onto the screw shaft, with the anchor section having a screw hole which fits the screw in the above upright position.