PURPOSE: To obtain an overhanging unit having open-hearted feeling by forming a frame of the overhanging unit in a U-shape, providing column sections to a U-shaped rear section only, and making unnecessary columns for a front open section.

CONSTITUTION: An overhanging unit 11 is so constituted that ceiling members 27, floor members 28 and window glass are provided to a frame 26. In addition, the frame 26 is so constituted that U-shaped frame members 34 formed of an upper beam section 31, a lower beam section 32 and a column 33, two beams 35 built between the up and down beam sections 31 and 31 and 32 and a plurality of beams 36 and a cross batten 37 are provided and, at the same time, that the column 33 is provided to columns 24 side of the unit side only. Column sections 22 of the overhanging unit and the columns 24 of the unit side are mounted and fixed with mounting members 45. According to the constitution, the front field of vision is opened, and the overhanging unit 11 having open- hearted feeling can be obtained.