PURPOSE: To enhance the power generation efficiency by previously imparting a swirling current velocity component in the reverse direction to a working fluid so that a swirling current velocity component for decreasing the current velocity in the conducting direction is offset and supplying the working fluid to a hot duct.

CONSTITUTION: A high temperature working fluid 1 from a high temperature heat- exchanger 3 is introduced to a spiral casing 21 and delivered to a hot duct 4 while swirling in the positive turning direction θ and passing through the hot duct 4 as a swirl flow having a current velocity in the positive turning direction θ. The working fluid 1 introduced into an MHD generator 6 is accelerated at the inlet of channel and enters into a sound velocity state at a throat section. Upon arriving at an MHD channel 1, the working fluid 1 is subjected to the electromagnetic driving force from an external field applying unit through an external field and bent in the negative turning direction θ. But since the current velocities in the positive and negative turning directions θ are offset in the MHD channel and the working liquid is delivered substantially linearly in the radial direction. Consequently, the radial current velocity is sustained at a high level and enhanced slightly thus enhancing the power generation efficiency.