A control device for a microgrid including: at least one heat engine power generator which is connected to a load via a distribution line and operates a heat engine to generate electric power; a natural energy power generation device which is connected to the distribution line and generates the electric power by use of natural energy; and an electric storage device including a storage battery and an electric power converter, the electric storage device being configured to cause the electric power converter to charge the storage battery with the electric power fed via the distribution line, the control device being configured to control the at least one heat engine power generator to perform and stop power generation and control the electric storage device to charge or discharge the storage battery, to maintain the storage battery in a chargeable or dischargeable state, characterized in that the electric storage device is configured to cause the electric power converter to discharge the storage battery to feed the electric power to the distribution line, the control device firstly supplies the electric power generated in the natural energy power generation device to the load to meet the electric power demand of the load, and if the electric power supplied by the control device is deficient, the control device controls the heat engine power generator and the electric storage device in such a manner that the control device causes the heat engine power generator to generate the electric power at a constant amount, and the storage battery of the electric storage device to be charged or discharged to compensate for surplus or deficient electric power of total electric power which is a sum of the electric power generated in the heat engine power generator and the electric power generated in the natural energy power generation device, with respect to the electric power demand of the load. at least one heat engine power generator which is connected to a load via a distribution line and operates a heat engine to generate electric power; a natural energy power generation device which is connected to the distribution line and generates the electric power by use of natural energy; and an electric storage device including a storage battery and an electric power converter, the electric storage device being configured to cause the electric power converter to charge the storage battery with the electric power fed via the distribution line, the control device being configured to control the at least one heat engine power generator to perform and stop power generation and control the electric storage device to charge or discharge the storage battery, to maintain the storage battery in a chargeable or dischargeable state, characterized in that the electric storage device is configured to cause the electric power converter to discharge the storage battery to feed the electric power to the distribution line, the control device firstly supplies the electric power generated in the natural energy power generation device to the load to meet the electric power demand of the load, and if the electric power supplied by the control device is deficient, the control device controls the heat engine power generator and the electric storage device in such a manner that the control device causes the heat engine power generator to generate the electric power at a constant amount, and the storage battery of the electric storage device to be charged or discharged to compensate for surplus or deficient electric power of total electric power which is a sum of the electric power generated in the heat engine power generator and the electric power generated in the natural energy power generation device, with respect to the electric power demand of the load.