In this research, a representative type of the housing plan was extracted on the basis of elements that exert the influence on the discrimination of the plan type, in other words, plan composition. Firstly, ‘connection type of the room’ and ‘composition type of LDK (living room, dining room and kitchen)’ were selected as elements of the plan type. Secondly, three forms of ‘connection type of the room’ became clear namely ‘middle corridor type’, ‘living room centered type’ and ‘entrance hall type’, as the factors that discriminate plan composition specifically. Thirdly, ‘LD/K type’ and ‘L/D/K type’ were confirmed as the factors in ‘composition type of LDK’. Finally, four combinations of plan type, such as ‘living room centered type-LD/K type’, ‘middle corridor type-LD/K type’, ‘living room centered type-L/D/ K type’ and ‘entrance hall type-LD/K type’ were confirmed as the representative types. These four combinations are the representative plan types of the urban LDK houses in Japan.