A damper with an air spring includes: a damper main body having a cylinder and a piston rod inserted into the cylinder; and a cylindrical diaphragm attached to a side of the cylinder at a first end thereof and to a side of the piston rod at a second end thereof and forming an air chamber around the damper main body, in which a first attachment case to which the first end of the diaphragm is attached is fitted on an outer periphery of the cylinder, and an inner-diameter step portion of the first attachment case is brought into abutting contact with an upper end portion of the cylinder in an axial direction thereof, while a second attachment case to which the second end of the diaphragm is attached is fixed to the piston rod.