The purpose of this study is to analyze the residential space composition and extension of Jeonja-jip and Dureong-jip in Samcheok region. The results of this study are as follows. It appears three residential plan types - Jeonja-jip with Anmaru(a room made of wooden floor), Jeonja-jip without Anmaru and Dureong-jip with Anmaru- in survey region. It was needed the extension of residential space at Jeonja-jip(a house type with two-row rooms which be composed of 田type under one roof) and Dureong-jip(a house type with inner floor which be surrounded by rooms under one roof) because of shortage of sleeping space, working space and keeping space owing to growing large family. The solutions of these shortages will be the extension of space in houses. Jeonja-jip's basic type which is the Kyup-Jip(a house type with two-row rooms under one roof) of 一 type with 6 Kans(Kan, a unit to count room to divided with four posts) is transformed and extended to 田shaped house with 11 Kans toward X-axis orientation. Dureong-Jip's basic type which is ㄱ type with 7 Kans is transformed and extended to the Sekyup-Jip with 9 Kans and the Nekyup-Jip(a house type with four-row rooms under one roof) with 12 Kans toward Y-axis orientation by insertion and addition. Jeonja-jip was developed into Kyup-Jip with front 4 or 5 Kans and side 2 Kans instead of being done into Sekyup-jip or Nekyup-Jip with insufficient day lighting and ventilation problems. Jeonja-jip and Dureong-jip were stronger than any other traditional houses in tendency to reserve Magu(cowshed) and Chikkan(toilet) in a house.