PURPOSE: To improve the solar-heat utilization efficiency and stabilize power generation performance by connecting a heat accumulator through a branched steam pipe onto main steam pipes which connect a light and heat collector and a steam turbine.

CONSTITUTION: The captioned apparatus collects the solar heat by a light and heat collector 1 and transforms heat collecting medium into superheated vapor, which is supplied into a steam turbine 4 to carry-out work, and a power generator 5 is driven, and electricity is generated. The steam which comes from the steam turbine 4 is condensed in a condenser 6 and returned into the light and heat collector 1. In this case, a branched steam pipe 5 is connected between the main steam pipes 11 and 12 which connect the light and heat collector 1 and the steam turbine 4, and a heat accumulator 16 consisting of a heat accumulator 17 and an accumulator 22 is connected to the branched steam pipe 15. When the amount of the steam consumed in the steam turbine 4 is more than the amount of the heat-collectred steam, the steam stored in the accumulator 22 is liberated, and the heat accumulator 17 is operated reversely to liberate heat into the steam turbine 4.