A suction surface of a blade forming a blade row of an axial compressor includes a concave region having a negative curvature at a leading edge part, and a flat region having substantially zero curvature continued rearwardly of the concave region, so that multiple compression waves are generated, enabling moderation of magnitude of a 1st passage shock to reduce pressure loss and suppress boundary layer separation on the suction surface. Providing a concave region having a negative curvature in a frontal part on a pressure surface of the blade suppresses an increase in the airflow velocity in the frontal part, thus weakening a 2nd passage shock generated on the pressure surface to enable reduction of pressure loss. The concave region of the pressure surface may be extended from a position having a chord length of no greater than 10% to a position having at least 20%.