The image sensor 15 of the information processing apparatus 1 can capture the retroreflective sheet 17 subjected to infrared light emitted from the infrared emitting diodes 11 since the retroreflective sheet 17 is exposed when the open-close portion 19 is opened. Therefore, it is possible to detect the input device 3. On the other hand, when the open-close portion 19 is closed, the image sensor 15 can not capture the retroreflective sheet 17 since the reflective sheet 17 is not exposed. Therefore, the input device is not detected.