Abstract
Walter Benjamin suggested 'porosity' as an important factor for making urban life and space when he studied and read european cities especially Napoli. Though the porosity he suggested was a little primitive and "barbarous", it becomes an important concept to make urban life inhabitable and urban space fertile. We studied a theoretical background for the application of porosity to urban architecture and experimentally probed a readability of the city Busan with it. First, we studied on reading methodology of 'image', 'trace' and 'body' as a basic theory to read the 'metropolis'. With this background we could establish 4 characteristics of urban porosity, ambiguities of "inside and outside", "old and new", "public and private", and "improvision and theatericality". With this concept of Benjamin's porosity we could read and analyse that of Busan Metropolis.