To enable a spring unit with a damper to maintain its stable damping force for a long and repeated application period and moreover simply attain a desired damping force.

This spring unit equipped with a damper has a torsion coil spring 11 forming a coiled part 11a between its both ends, and a cylindrical spring material 12 having a continuous slit 13 throughout its longitudinal body so that it may be approximately C-shaped in section. The cylindrical spring material 12 is manufactured in an outer diameter larger than the inner diameter of the coiled part 11a, and pressed fit within the coiled part 11a in the state of its outer diameter shrunken under pressures. When the end 11b or 11c of the torsion coil spring 11 is turned round, a friction force generated between the torsion coil spring 11 and the cylindrical spring 12 while the coiled part 11a is changing its inner diameter is used as the force for damping the movements of the end 11b or 11c of torsion coil spring 11.