An electric power supply-and-demand control apparatus comprising: a measuring module (2, 3) which measures an output power characteristic of dispersed power sources arranged in various places in an electric power system; and a determination module which determines based on the output power characteristic measured by the measuring module (2, 3) whether to set each of the dispersed power sources in various places as a dispatching object for an electric power supply-and-demand plan at a specific time on a specific date, characterized in that the dispersed power sources include natural energy power supplies that receive natural energy and generate electricity and electric power storage devices that store electric power generated by the natural energy power supplies, the measuring module (2, 3) measures information on a characteristic of the generated electricity of the natural energy power supplies and the charging state of and a performance degradation characteristic of the electric power storage devices, and the determination module includes a first determination function of determining based on a fluctuation range of the generated electricity shown by the information measured by the measuring module (2, 3) whether to set each of the natural energy power supplies generating electric power constituting the generated electricity as a dispatching object for an electric power supply-and-demand plan at the specific time on the specific date, and a second determination function of determining based on the charging state of and the degree of the performance degradation of the electric power storage devices shown by the information measured by the measuring module (2, 3) whether to set each of the electric power storage devices in various places as a dispatching object for an electric power supply-and-demand plan at the specific time on the specific date. a measuring module (2, 3) which measures an output power characteristic of dispersed power sources arranged in various places in an electric power system; and a determination module which determines based on the output power characteristic measured by the measuring module (2, 3) whether to set each of the dispersed power sources in various places as a dispatching object for an electric power supply-and-demand plan at a specific time on a specific date, characterized in that the dispersed power sources include natural energy power supplies that receive natural energy and generate electricity and electric power storage devices that store electric power generated by the natural energy power supplies, the measuring module (2, 3) measures information on a characteristic of the generated electricity of the natural energy power supplies and the charging state of and a performance degradation characteristic of the electric power storage devices, and the determination module includes a first determination function of determining based on a fluctuation range of the generated electricity shown by the information measured by the measuring module (2, 3) whether to set each of the natural energy power supplies generating electric power constituting the generated electricity as a dispatching object for an electric power supply-and-demand plan at the specific time on the specific date, and a second determination function of determining based on the charging state of and the degree of the performance degradation of the electric power storage devices shown by the information measured by the measuring module (2, 3) whether to set each of the electric power storage devices in various places as a dispatching object for an electric power supply-and-demand plan at the specific time on the specific date.