A damper comprising: a cylinder tube having a first end and a second end, wherein the first end can be connected to one part of a member as an object of damping; a fixing rod guide for closing the second end of the cylinder tube; a movable rod guide axially and slidably fitted in the cylinder tube on the first end side of the cylinder tube; a piston axially and slidably fitted in a middle section in the axial direction of the cylinder tube; a main piston rod extending from the piston on the second end side of the cylinder tube, and passing through the fixing rod guide, wherein the main piston rod can be connected to another part of the member; a sub-piston rod extending from the piston on the first end side, and passing through the movable rod guide; and a spring disposed coaxially with an axial center of the cylinder tube and normally biasing the movable rod guide toward the piston; wherein a first oil chamber is defined between the fixing rod guide and the piston, a second oil chamber is defined between the movable rod guide and the piston, and a damping force generation oil passage is provided for connecting the first and the second oil chambers (42, 43); characterized in that the damper further comprises: a regulating valve for adjusting an opening of the damping force generation oil passage provided on the axial center of the sub-piston rod; and an operation rod fitted in an axial center hole formed on the axial center of the sub-piston rod, said operation rod having one end connected to the regulating valve and having the other end as an operating section; wherein an operation hole for allowing the operating section to be operated outside of the first end is formed on the first end of the cylinder tube.. a cylinder tube having a first end and a second end, wherein the first end can be connected to one part of a member as an object of damping; a fixing rod guide for closing the second end of the cylinder tube; a movable rod guide axially and slidably fitted in the cylinder tube on the first end side of the cylinder tube; a piston axially and slidably fitted in a middle section in the axial direction of the cylinder tube; a main piston rod extending from the piston on the second end side of the cylinder tube, and passing through the fixing rod guide, wherein the main piston rod can be connected to another part of the member; a sub-piston rod extending from the piston on the first end side, and passing through the movable rod guide; and a spring disposed coaxially with an axial center of the cylinder tube and normally biasing the movable rod guide toward the piston; wherein a first oil chamber is defined between the fixing rod guide and the piston, a second oil chamber is defined between the movable rod guide and the piston, and a damping force generation oil passage is provided for connecting the first and the second oil chambers (42, 43); a regulating valve for adjusting an opening of the damping force generation oil passage provided on the axial center of the sub-piston rod; and an operation rod fitted in an axial center hole formed on the axial center of the sub-piston rod, said operation rod having one end connected to the regulating valve and having the other end as an operating section;