PURPOSE: To eliminate the need for a troublesome operation to set a page with a special key, by discriminating automatically the switching of pages by means of a light emitting element and a photodetector which are provided at the page side and the pedestal side, respectively.

CONSTITUTION: A page type input device contains a pedestal 1, and this pedestal 1 has plural key groups 4 arranged into a matrix form. At the same time, plural page groups 2 are set on the pedestal 1, and each page has the holes corresponding to the keys of the groups 4. Thus each key 4 is put into the hole when a page is turned over via the guides 5 and 6. As a result, the item of input corresponding to the input key can be varied with each switching of the page. Furthermore, a light emitting diode 3 is provided to each page 2, and a photodetector is provided to the pedestal 1. Then the change of output due to the switching of pages is detected for the detector 8 to perform the switching of each page.