A greenhouse comprising two structures (1, 1) joined to each other. Each of the structures comprises a rectangular frame body (11) disposed horizontally, a rectangular main beam (12) vertically disposed on the frame body (11), and a principal rafter member (13) supporting the main beam (12). The greenhouse is characterized in that an interval between column members (2) disposed indoors in the lateral direction and an interval in the depth direction are set approximately equal to each other by supporting four corners of a joined body on the column members (2). The joined body is formed by joining the frame bodies (11) to each other, set so that the ratio of the lengths of its two sides crossing perpendicularly to each other is approximately 1:1, and comprises a connection member (15) installed across the intersected portion of the main beam (12) with the principal rafter member (13) of one structure (1) and the intersected portion of the main beam (12) with the principal rafter member (13) of the other structure (1).
