Abstract: This invention relates to a screw stopper including an anti-freeze device used for water pipe valve and fitted to the lower end portion of an open/close movable valve of said water pipe valve comprises: a small perforation penetrated centrally on the lower portion of the said screw stopper; a water-through recess formed on a countersink portion of the said screw stopper; a small movable member including a small valve for opening and closing an aperture of the said small perforation, and said small movable member partially defining an water-through passage; a pair of springs for holding said small movable member, at least of which is made of shape-memory alloy; an outer cylinder for holding said pair of springs screwed and fitted to the said screw stopper; and a packing for sealing up water by a valve seat.