To solve the problem that a detachable bookmark made of one sheet or a bar and disclosed at present needs its repeated removal and attachment being inevitable at every change of an marking page or the problem that a sheet having a hole provided therein and a marking string attached to the sheet takes very much time, resulting in heightening the production cost thereof.

In this bookmark A, at least a binding part 2 for binding to the paper binder 4 of a paper substituting type note book B is provided in sheet base material 1 and, at the same time, at least a marking part 3, the length of which is longer than the distance between the top edge and the tail edge of a paper 6 bound to the paper binder 4, is formed beyond the side edge nearer to the paper binder 4 of the sheet base material 1 bound to the paper binder 4.