Abstract: A fastening device for schedule folder covers with a side plate to join two covers of schedule folder, wherein both ends of the side plate is connected with a side chain band similar to a metallic watchband and identical to the width thereof, and a connecting zipper fitted to both sides of the side chain band and the edge of the covers, and wherein a closed state between two covers and the side chain band is created by means of the connecting zipper while a soft parting member can be mounted inside of the side chain band, if necessary, for dividing the internal space of the folder in accordance with the using requirements and for enhancing the flexible using of the whole internal space.