A data inputting apparatus includes a plurality of keyswitches, an optical module, a sensing module and a processing module. The keyswitches are disposed on the data inputting apparatus. The optical module is disposed on a first side of the data inputting apparatus and is used for emitting a plurality of lights along a first direction, and the lights are corresponding to the keyswitches respectively. The sensing module is disposed on a second side opposite to the first side and is used for receiving the lights and generating a sensing result. The processing module is coupled to the sensing module. When one of the keyswitches is pressed, one of the lights is blocked by the pressed keyswitch resulting in the sensing module adjusting the sensing result, and the position of the pressed keyswitch is determined by the processing module based on the sensing result.