The invention relates to a buckle for fastening a sports boot and to a sports boot including such buckle. The buckle includes a baseplate, a lever connected to the baseplate by a first transverse articulation about an articulation axis, the lever having a gripping portion, a connecting rod articulated to the lever by a second transverse articulation about a second articulation axis, a loop mounted at the other end of the connection rod. The lever has a lever body that has a guiding tube for each of the articulation axes. The body is formed by a sheet of material, and the sheet is folded along folding lines that are parallel to each of the articulation axes to form the tubes for guiding the articulation axles.