A truss type extruded aluminum section (1) is formed of a pair of planar plates (2)(3) and ribs (4)(5)(6), wherein hollow portions (7)(8)(9) are formed within the section (1) by the ribs (4)(5)(6) and the planar plates (2)(3). Vibration-damping resin is provided on the inner surfaces of hollow portions (7)(8)(9), and particularly on the inner surface of the planar plate (3) and on a single surface of the inclined rib (4). With this arrangement, the vibration energy bending the planar plate (3) and the rib (4) is converted into a heat energy. In the case of manufacturing such truss type extruded aluminum vibration-damping section (1), for making easy the insertion of the vibration-damping resin in the hollow portion, the vibration-damping resin is stuck on a plastic film (11) to form a long planar body. The plastic film (11) serves as a cover or an adhesive. Moreover, in the case of directly inserting the vibration-damping resin sheet (14), the vibration-damping resin sheet (14) is subjected to embossing on the adhesive-bonding side for allowing air to escape. Additionally, in the case using an age-hardening type aluminum alloy, the adhesive-bonding for the vibration-damping resin by heating is performed along with the heat treatment for age-hardening.