Panasonic FX-11A slim body analog fiber sensor incorporates an analog voltage output of 1 to 5 V. Being only 10 mm 0.394 in thick, it can be mounted in a narrow space. In combination with various types of fibers and the ultracompact digital panel controller, CA2 series, FX-11A can be used for various applications, such as, height evaluation, level detection by differential sensing, etc. The saturation indicator lights up when the output reaches 5 V. Hence, the sensitivity can be easily adjusted even without using a tester. Moreover, an incident beam indicator which brightens up in proportion to the amount of incident beam (output voltage) is also incorporated. Two sets of fibers can be mounted close together or face to face.