A high performance airfoil of a compressor is provided that can achieve a reduction in secondary loss and in cross flow and ensuring of reliability.
An axial compressor includes a plurality of stator vanes 5 attached to an inner surface of a casing 3 defining an annular flow path and a plurality of rotor blades 4 attached to a rotating rotor 2 defining the annular flow path. A flow path is defined between a pressure surface 22 of a stator vane 5 and a suction surface 21 of a stator vane 5, the vanes being circumferentially adjacent to each other, or between a pressure surface 22 of a rotor blade 4 and a suction surface 23 of a rotor blade 4, the blades being circumferentially adjacent to each other. The flow path is formed so that a throat portion at which a flow path width is minimized is provided on the upstream side of 50% of an axial chord length and an axial flow path width distribution extending from the leading edges 23 to trailing edges 24 of the vanes or the blades defining the flow path therebetween has an inflection point on the downstream side of the throat portion.