A demand control device performs demand control in which energy consumption of heat source units is suppressed with regard to a heat source system having a plurality of the heat source units with capacities and/or output characteristics that are different. The demand control device includes a receiving section, a collecting section, an energy suppression amount value calculating section, a heat source output determining section, and a driving section. The receiving section receives a demand signal which requests starting of the demand control. The energy suppression amount value calculating section calculates an energy suppression amount value relating to an energy amount suppressed during the demand control. The heat source output determining section determines an output individually with regard to each of the plurality of heat source units based on the energy suppression amount value. The driving section drives each of the plurality of heat source units using the output.