To provide an automatic bookmarker, which can smoothly turn over page sheets with a lighter force under the stabilized state of a bookmarker body.

The automatic bookmarker 13 comprises one rectangular sheet made of one synthetic resin sheet. A second base sheet 16 is turned down along first portions 25a and 25b to a first base sheet 15. The bookmarker body 18 is so constituted as to extend from the first base sheet 15 at second portions 27a and 27b locating between the first portions 25a and 25b. The bookmarker body 18 comprises a pair of bookmarker pieces 20a and 20b respectively extending from the second portions 27a and 27b and getting nearer to each other as the pieces part from the first base sheet 15, resulting in connecting together at every end part into a body to an apex part 24. In addition, a spanning piece 22 is put up at the intermediate parts of the bookmarker pieces 20a and 20b for spanning.