A carbon dioxide supply device provided with a combustor (1), a refrigerator (3), and a heat exchanger (6) for heat absorption through which a fluid flows having been cooled in a refrigeration cycle of the refrigerator (3), the carbon dioxide supply device being characterized in that exhaust gas containing carbon dioxide and obtained by combustion in the combustor (1) is passed through the heat exchanger (6) for heat absorption and cooled, and is supplied to a horticultural greenhouse facility.
