A span type greenhouse has structural units installed parallel to one another over an entire length of a bay defined under a span. The ratio of a distance between a top of the greenhouse and a horizontal straight line passing through top ends of side posts over the bay width is less than 1/5. This greenhouse also has central double opening windows. In a transverse profile of the greenhouse, and angle formed between a straight line tangential to an arch segment in a transverse plane of the greenhouse at a side lintel, and a straight line intersecting a hinge axis and the end of a closed side window in the transverse plane of the greenhouse is non-zero in the direction of a concave side of the greenhouse profile, this break in slope procuring a slope for the closed window that is at least 15°.