Disclosure herein is to an electronic device installed with an optical indexing module. The electronic device is such as a computer device. The optical indexing module is provided for controlling the cursor generated by a computer operating system. The indexing module may be disposed near the touch-control pad of a laptop computer; or cooperated with other control interfaces for controlling the cursor and performing operations. The electronic device may also be a cursor control device connected with a computer system. The cursor control device is disposed with the optical indexing module. In appearance, an opening is formed on the device for the optical indexing module allowing emitting and receiving lights there-through. The multiple sensing cells arranged in an array receive the reflected lights. An indication signal for controlling the cursor is generated by determining a moving direction according to an energy difference made among the arrayed sensing cells.