A keyboard device includes a base, a plurality of keys, a light source module, a first sensor, a second sensor, and a control module. An ambient luminance of the plurality of keys is detected by using the first sensor. When the ambient luminance is less than an ambient luminance at which the second sensor can capture a required image, the control module turns on the light source module to provide a light source for the plurality of keys to improve the ambient luminance, so that the second sensor to can clearly capture the required image and obtain the required data by means of analysis.