In a method of examining the states of alignment of glass fibers in a pair of ribbon fiber cables by observing their images obtained in two directions, a reflecting mirror is located adjacent to glass fibers of a pair of ribbon fiber cables. Illuminating light is introduced into the glass fibers of the fiber cabes in a direction different from the normal direction of a plane formed by the glass fibers, and an image formed by the illuminating light which is reflected by the reflecting mirror and then passed through the glass fibers and another image formed by the illuminating light which is passed through the glass fibers and then reflected by the reflecting mirror are observed. According to the examining method, the optical axes of two images obtained on the light receiving side can be made parallel to each other to keep the two images extremely near to each other. Therefore, the distance along which the pickup system must be moved can be made short. This makes the system small-sized and the image processing time short. In addition, the objective used in the pickup system, may have a low magnification. Further, all of the glass fibers can be observed once on a screen and the adjustment of focus relative to the glass fibers may be conducted one time when they are observed in each of two directions. Furthermore, their shift from that axis along which they should be aligned can be detected with a higher accuracy.