A touch pad device, constructed in an electronic apparatus, includes a touch module further having a touch pad and an FPCB and a plurality of metal domes located under the FPCB. The FPCB located under the touch pad further has a plurality of holes and a plurality of sensor elements, in which the holes are dispersed amid the sensor elements. Each of the metal domes represents a function key. By providing the plural holes surrounding the sensor elements, flexibility of the touch pad device can be enhanced and over deflection upon the touch module can be avoided, while pressing the function key.