PURPOSE: To utilize the surplus midnight power, accumulating it as a potential energy quantity and converting this stored potential energy into electric energy, and to supply it at the daytime when an electric power demand is much, for power generation.

CONSTITUTION: This generating set is provided with a weight member 11, utilizing a mass of midnight power, and winding up this weight member 11 situated in a down end or down position, and it is shifted to an up end or up position, and potential energy is given and energized for maintenance, while it is also provided with a generator 51, and the potential energy in the up end or up position of the weight member 11 is released free, then this generator 51 is driven by driving energy with the dead weight descent, whereby it is constituted so as to secure a generating action in this way.