An optical scanner suitable for scanning a vertical object. The optical scanner has a scanning body, a focusing device and a scanning module. The scanning body has a transparent window, the focusing device has an arm, a reflective mirror and a lens. One end of the arm is coupled to the scanning body, and the reflecting mirror and the lens are disposed on the arm. The scanning module is disposed in the scanning body with a shell, a lens and an optical sensor. The shell has a light cone opening, and the lens and optical sensor are disposed within the shell. The image of the vertical object is focused by the focusing device on the transparent window, incident to the scanning module via the light cone opening, and refracted by the lens to form an image on the optical sensor.