To provide an axial flow turbine to remarkably improve the efficiency of a blade by a method wherein when device having a throttle flow passage wall is formed in the blade as seen from a meridian plane is employed, the occurrence of a reverse flow vortex to a throttle flow passage wall and boundary layer separation is suppressed.

An axial flow turbine is formed such that an outer wall throating streamline 36 on the belly side curved in a protrusion state toward a turbine shaft 32 and an outer wall throttling streamline 38 on the back side are formed at the tip part of a stationary blade 28. The blade height of the outer wall throating stream line 38 on the back based on a radius passing through the center of the turbine shaft 32 is reduced to a value lower than that of the outer wall throating streamline 36 on the belly side and the blade height of the outer wall throating streamline 38 on the back side of one stationary blade is caused to approximately coincide with that of the outer wall throating streamline 36 on the back side of the other adjoining stationary blade.