To solve such problems of a traditional leather backpack that cash or important papers put in a pocket in a flap of the backpack may fall and be lost when the opening of the pocket is turned down because the flap is opened/closed with its bottom edge being the center of the movement, and that when a zipper is attached to the pocket to prevent important articles stored there from falling, a user may seldom open/close the zipper in lesson and rest hours and not notice the existence of such articles, so that the user often forgets to hand or show the articles to teachers or parents.

An open/close zipper 2 is attached to the opening at the bottom edge of a translucent material 1 through which articles can be seen even when the material is double-layered. The top edge and both sides of the material 1 are sewn to the rear surface of the flap 3 of a backpack, and a first pocket P1 is formed between the layers of the material 1. And a second pocket P2 is formed between the rear surface of the double-layered material 1 and the flap 3.