Visibility is an important character of the river in the city. In Japan, numerous outdoor signboards are used along the urban river. This paper aims to use the index of “rate of signboard area” to decipher the visibility and its utilization in different spaces along the two rivers in the middle of Osaka. As the result, the bridge was found as the most effective factor which gives good vision and makes these signboards specially utilized. Next comes the pattern of riverside-road and building use, which both affect “rate of signboard area” evidently. Some subjects and methods available to riverside planning based on the result were proposed.
