To reduce the production cost of a greenhouse and further to enable the greenhouse to have a structure easily releasing the heat in summer.

This greenhouse 1 has rafters 3 arranged at 60 cm intervals so as to extend to the top of a roof. Pipes obtained by squashing circular pipes so as to have U-shaped cross sections are used as the rafters 3. Pillars 5 are arranged at 3 m pitch in the depth direction. Puncheons 7 are arranged between the pillars 5 and 5 at 60 cm pitch. Trusses 9 for reinforcement, connecting the upper parts of the pillars to each other in the horizontal direction are arranged in the width direction. The greenhouse 1 is formed into a multi-span type of small roofs. As a result, a principal ridgepole and a main building which are possessed by a conventional greenhouse are eliminated from the greenhouse 1 to simplify the structure and to reduce the production cost. The pillars 5 can be heightened compared to those of the large roof-type conventional greenhouse, to enable the heat to be released easily.