A compressed air energy storage power generation device 2 equipped with: a compressor 10 mechanically connected to a motor 30; a first pressure storage tank 12 storing compressed air from the compressor 10; an expansion device 14 driven by compressed air from the tank 12; a generator 28 mechanically connected to the expansion device 14; a first heat exchanger 18 that exchanges heat between a heat medium and the compressed air supplied from the compressor 10 to the tank 12; a second heat exchanger 22 that exchanges heat between the heat medium and the compressed air supplied from the tank 12 to the expansion device 14; a pressure sensor 13 that detects the state of charge (SOC) of the tank 12; SOC adjustment units 17, 34a, 34b, and 34c that adjusts the SOC; and a control device 40. The control device 40 controls the SOC adjustment units 17, 34a, 34b, and 34c such that the detected SOC is within an optimal SOC range while satisfying the requested power. Thus, in this compressed air energy storage power generation device 2 the SOC is controlled so as to be within an optimal SOC range, so the operating efficiency can be improved.