The invention discloses an adjustable horizontal guiding device for a crane. The adjustable horizontal guiding device comprises fixing seats, guiding pulleys and guiding pulley shafts. According to the adjustable horizontal guiding device, the structure that the radial clearances are adjusted by utilizing wedge blocks and butterfly-like spring groups is adopted; when the quantity or the thickness of gaskets connected with the fixing seats through the wedge blocks is increased or decreased, the guiding pulley shafts can be radially positioned and fixed by compressing the butterfly-like spring groups, and then the clearances can be adjusted continuously; meanwhile, all the work bearing force comes from the compressing force, the stability is high, and the defects that an eccentric shaft structure cannot be adjusted continuously and bolts are easy to loosen can be overcome; through bolted-connection waist-shaped mounting holes formed in the fixing seats, horizontal guiding pulley groups can be axially adjusted continuously, both the convenience and the rapidness can be achieved, and the defect that the guiding pulleys cannot work normally due to errors in the mounting and the abrasion to wheels can be overcome; meanwhile, fixing brackets need not be additionally arranged for the guiding pulley groups and can be directly connected onto lower cross beam side plates of the crane, thereby reducing the space required for the mounting and enhancing the universality; the adjustable horizontal guiding device can be mounted and used as long as mounting and connecting holes are arranged on the side plates; and the mounting process is simple and rapid.