PROBLEM TO BE SOLVED: To provide a drive control method of an internal combustion engine, along with a greenhouse cultivation system, capable of reducing a nitrogen oxide concentration in exhaust gas supplied to a greenhouse, while maintaining a high drive efficiency of the internal combustion engine.SOLUTION: The drive control method of the internal combustion engine supplies exhaust gas 11a containing carbon dioxide to a greenhouse 2 via an exhaust channel 13 including exhaust gas cleaning units 18A, 18B. When a carbon dioxide concentration in the greenhouse 2 is lower than a carbon dioxide concentration range required in the greenhouse and a nitrogen oxide concentration in the greenhouse 2 is equal to or more than a nitrogen oxide concentration range required in the greenhouse 2, the internal combustion engine 11 is driven by stoichiometric combustion. In each case except for that, the internal combustion engine 11 is driven by lean burn.
