An axial flow compressor includes: an electric motor including a rotating shaft; a compression portion including a driving shaft connected without a speed-up gear to the rotating shaft of the electric motor and a rotor rotating together with the driving shaft, the compression portion driving the driving shaft and thereby compressing a working fluid; and a velocity reducing portion having a space for reducing the flow velocity of a working fluid discharged from a discharge opening of the compression portion. The rotating shaft of the electric motor is connected to the end of the driving shaft on the side of the discharge opening; and the velocity reducing portion is disposed so as to surround the electric motor.