PURPOSE: A lightweight shaped steel frame, and an arch shaped house structure using thereof are provided to improve the cross-sectional performance of the steel frame by extending a flange unit on one side of a web unit. CONSTITUTION: A lightweight shaped steel frame comprises the following: a first flange unit(13) extended from one end of a web unit(11); a second flange unit(15) with the wider width than the first flange unit, extended from the other end of the web unit; and the web unit including left and right webs(11a, 11b). The second flange unit includes left and right flanges(15a, 15b) located on one ends of the left and right webs, and bent in multiple stages toward the web unit. The left and right webs include embossing protrusions(12a, 12b) protruded from the center of each web.
