Steps are extremely common in the living and working space. They can also be found outdoors, inparks, streets, and building sites. However, many injuries and accidents occur on and around steps,whose major causes are missing the step, stumbling and tumbling. The visibility of the step seems tobe one of the most essential factors in these accidents. In the past years, some researchers studied theinfluence of visual characteristics of steps and tried to quantify their visibility by applyingpsychological methods. However, appropriate methods for quantifying the visibility of steps have notyet been established. In this research, at first, we composed the sensory scales of step visibility, andexamined the contents and tendency of the relations of these scales. In the sensory tests, the testsubjects were asked to judge the visibility of steps when viewing them at a fixed position from above.After the tests, we considered that the nosing visibility is independent of the height visibility, and thetotal visibility of the steps and height visibility have almost the same meaning in the conditions of thisresearch. Second, we examined the relation between the height visibility of steps and visualcharacteristics of the step photos. In the sensory tests, test subjects were asked to judge the horizontaldeviation of the step photos which were taken at the position of the right and left eyes. After the tests,we considered that the horizontal deviation is a major factor when judging the riser height of step.