A ventilation control device (2) includes a total exhaust air volume reader (16), an exhaust device specification reader (17), an exhaust air volume distributor (18), and an exhaust air volume instructor (19). The total exhaust air volume reader (16) reads the total exhaust air volume set to a building. The exhaust device specification reader (17) reads a maximum exhaust air volume of each of exhaust devices (3) as a specification of the exhaust device (3). The exhaust air volume distributor (18) sets the exhaust air volume of each exhaust device (3) by distributing the exhaust air volume read by the total exhaust air volume reader (16) according to the maximum exhaust air volume of the exhaust device (3) read by the exhaust device specification reader (17). The exhaust air volume instructor (19) instructs, to each exhaust device (3), the exhaust air volume set by the exhaust air volume distributor (18).