The utility model discloses an erecting device for erecting variable-height steel beam sections. Relating to the field of bridge laying, the device comprises a slideway, a bracket arranged on the slideway and a traction counterforce seat detachably arranged on a sliding rail, the slideway is arranged on the lower-layer bridge surface of the double-layer bridge, the ground between the double bridgepiers or the trestle; the slide way comprises two slide rails which are arranged in parallel; the support comprises at least four stand columns. Pull rod is arranged between stand columns, all the stand columns and the pull rods form a truss type structure. The bottoms of the stand columns are used for sliding on sliding rails. The top of the stand column is detachably provided with a supportingbase which is adjustable in height and used for supporting the steel beam segments. A driving device is fixed on the traction counter-force seat and connected with the stand column which is located onthe same sliding rail and close to the traction counter-force seat through a rope, the situation that the height of the steel beam section is changed in the conveying process of the steel beam section is avoided, and therefore the final bridging line type of the steel beam can be guaranteed.