An axial compressor that can remove an attachment within a groove of a casing and recover an effect of suppressing stall on rotor blades, and a gas turbine provided with the axial compressor, are provided. The axial compressor includes a compressor body 6 and a sprayer 9 for spraying droplets in suction gas of the compressor body 6 so that the droplets are introduced into the compressor body 6 and evaporate. The compressor body 6 includes a casing 11, a rotor 12, rotor blades 13, and stator vanes 14. A groove 21 is formed in an inner circumferential surface of the casing 11 so as to be positioned around rotor blades 13 arranged on a front stage side. A purge system 23 is provided that supplies high-pressure air to the groove 21 through communication holes 22.