Abstract: An indexing device is constructed such that a plurality of cards are filed in order between a base member of the device and a cover member pivotaly secured to the base member. The cards have protruding marginal edges such that, when the cards are filed in order in the device, the exposed portions of the respective marginal edges are in a sequential step-wise arrangement. A plurality of push-buttons are provided in the cover member in correspondence to the marginal edges of the respective cards such that one can select the desired card or page and open the cover member together with that card by a single push-button pressing operation.