An air suspension in an embodiment includes: a cylinder; a piston rod; a rod-side member disposed on the lower end side of the piston rod; a diaphragm; an axle-side attachment member having an upper end side of which is fixed to an opening at a lower end of the rod-side member, the axle-side attachment member including a fixing section for fixing the piston rod and an attachment hole joined to an axle; a gas passage formed in the axle-side attachment member, one end of the gas passage being opened to an upper end face of the axle-side attachment member and the other end of the gas passage being opened to a side section of the axle-side attachment member; and a valve section provided at the opening of the other end of the gas passage.