Axial-flow compressor and modification method

An axial-flow compressor (100) includes: stator vane rows (1) that are located at the plurality of stages and include variable stator vanes (3) that extend in a radial direction of the axial-flow compressor (100) and rotate around rotary shafts (2) of the variable stator vanes (3) so as to adjust angles of the variable stator vanes (3); a plurality of rings (11) that are connected to the stator vane rows (1) located at the plurality of stages and drive and rotate the variable stator vanes (3) of the stator vane rows (1) that correspond to the rings (11), respectively; a plurality of levers (12) that correspond to the plurality of rings (11), respectively.