An optical module using a linear sensor for identifying images includes a circuit board, a linear sensor installed on the circuit board, a light source set installed on the circuit board, and an optical element. The optical element includes a first plane, a second plane paralleling the first plane, wherein a distance between the second plane and the circuit board is shorter than a distance between the first plane and the circuit board, a first total reflection plane between the first plane and the second plane, for totally reflecting light provided by the light source set, and a second total reflection plane between the first plane and the second plane, for totally reflecting reflected light of the first total reflection plane to the linear sensor.