In a sensor assembly, a hole-shaped sensor support portion is formed at a sensor printed circuit board (PCB), a touch sensor is disposed at the sensor support portion, and an elastic member is installed at a rear surface of the sensor PCB. In addition, a sensor assembly according to an embodiment of the present invention may include a sensor PCB on which a copper coating film which constitutes a circuit is printed on a top surface of a plastic material, a touch sensor seated on a sensor support portion formed at the sensor PCB, and a cover member which is attached onto a rear surface of the sensor PCB and covers the sensor support portion.