A solar thermal power generation system comprising: a solar heat collection device which collects solar heat and thereby heats up molten salt as a primary heat medium; a solar heat accumulation/radiation device including a low-temperature tank which stores molten salt to be supplied to the solar heat collection device, a high-temperature tank which stores high-temperature molten salt heated by the solar heat collection device, and a secondary heat medium heater which heats up a secondary heat medium by using the high-temperature molten salt supplied from the high-temperature tank as a heating medium; and a compressor/high-temperature turbine power generation device including a compressor which generates compressed air as the secondary heat medium by compressing air taken in from the atmosphere to a prescribed pressure, a high-temperature air turbine which drives a generator by taking in the compressed air heated by the secondary heat medium heater, and a line (51, 53) connected to the secondary heat medium heater and the high-temperature air turbine, and an inlet valve for adjusting the flow rate of the compressed air flowing into the high-temperature air turbine; characterized by an electric motor which drives the compressor; and an inverter which supplies power to the electric motor, wherein the electric motor receives revolution speed control from the inverter; a bypass system which leads the compressed air heated by the secondary heat medium heater to a high-temperature air turbine exhaust header pipe while bypassing the high-temperature air turbine, the bypass system being branched from the line (51, 53); a bypass valve for adjusting the flow rate of the compressed air flowing through the bypass system; a control unit regulating the flow rate and the pressure of the compressed air to be introduced to the high-temperature air turbine at predetermined values by adjusting the open angles of the bypass valve and the inlet valve. a solar heat collection device which collects solar heat and thereby heats up molten salt as a primary heat medium; a solar heat accumulation/radiation device including a low-temperature tank which stores molten salt to be supplied to the solar heat collection device, a high-temperature tank which stores high-temperature molten salt heated by the solar heat collection device, and a secondary heat medium heater which heats up a secondary heat medium by using the high-temperature molten salt supplied from the high-temperature tank as a heating medium; and a compressor/high-temperature turbine power generation device including a compressor which generates compressed air as the secondary heat medium by compressing air taken in from the atmosphere to a prescribed pressure, a high-temperature air turbine which drives a generator by taking in the compressed air heated by the secondary heat medium heater, and a line (51, 53) connected to the secondary heat medium heater and the high-temperature air turbine, and an inlet valve for adjusting the flow rate of the compressed air flowing into the high-temperature air turbine; characterized by an electric motor which drives the compressor; and an inverter which supplies power to the electric motor, wherein the electric motor receives revolution speed control from the inverter; a bypass system which leads the compressed air heated by the secondary heat medium heater to a high-temperature air turbine exhaust header pipe while bypassing the high-temperature air turbine, the bypass system being branched from the line (51, 53); a bypass valve for adjusting the flow rate of the compressed air flowing through the bypass system; a control unit regulating the flow rate and the pressure of the compressed air to be introduced to the high-temperature air turbine at predetermined values by adjusting the open angles of the bypass valve and the inlet valve.