The present invention relates to improvements in door stoppers for keeping doors open. More particularly, the invention offers door stoppers which facilitate opening/closing of the door by the attraction of a permanent magnet, prevent damage to the attracting member by causing the attracting member and the attracted member comprising such a door stopper to gradually attract each other by a buffer action, and make either one of the attracting member or the attracted member swingable so as to enable secure and stable attraction.