A method for manufacturing filter elements for an air filter, the method comprising the following steps of: a) Guiding a sheet of the filtering medium according to a direction of advance, the sheet comprising two longitudinal edges and a plurality of preforming lines transverse to the longitudinal edges, b) Providing a first crushing roller and a second crushing roller of the sheet, the first roller and the second roller being independently displaceable in a direction transverse to the direction of advance of the sheet and, c) Independently controlling the transverse displacement of the first crushing roller and the transverse displacement of the second crushing roller so that during the advance of the sheet, the first crushing roller forms a first series of embossed areas at the intersection with one preforming line out of two and that the second crushing roller forms a second series of embossed areas on each preforming line having an embossed area of the first series, d) Providing a first glue nozzle and a second glue nozzle, the first glue nozzle and the second glue nozzle being independently displaceable in a direction transverse to the direction of advance of the sheet, e) Depositing over the sheet of the filtering medium a first bead of glue connecting the embossed areas of the first series and a second bead of glue connecting the embossed areas of the second series, f) Folding the sheet of the filtering medium along each of the preforming lines so as to form a folded part comprising alternately high folds and low folds, the successive high folds being joined by the first series of embossed areas forming a lateral profile of at least one filter element and by the second series of embossed areas and the succession of low folds respectively forming a first plane and a second plane parallel to the plane of the guided sheet at step a), g) Carrying out a separation cutting of the folded part in a direction transverse to the direction of advance, to separate in a unitary manner the filter elements. a) Guiding a sheet of the filtering medium according to a direction of advance, the sheet comprising two longitudinal edges and a plurality of preforming lines transverse to the longitudinal edges, b) Providing a first crushing roller and a second crushing roller of the sheet, the first roller and the second roller being independently displaceable in a direction transverse to the direction of advance of the sheet and, c) Independently controlling the transverse displacement of the first crushing roller and the transverse displacement of the second crushing roller so that during the advance of the sheet, the first crushing roller forms a first series of embossed areas at the intersection with one preforming line out of two and that the second crushing roller forms a second series of embossed areas on each preforming line having an embossed area of the first series, d) Providing a first glue nozzle and a second glue nozzle, the first glue nozzle and the second glue nozzle being independently displaceable in a direction transverse to the direction of advance of the sheet, e) Depositing over the sheet of the filtering medium a first bead of glue connecting the embossed areas of the first series and a second bead of glue connecting the embossed areas of the second series, f) Folding the sheet of the filtering medium along each of the preforming lines so as to form a folded part comprising alternately high folds and low folds, the successive high folds being joined by the first series of embossed areas forming a lateral profile of at least one filter element and by the second series of embossed areas and the succession of low folds respectively forming a first plane and a second plane parallel to the plane of the guided sheet at step a), g) Carrying out a separation cutting of the folded part in a direction transverse to the direction of advance, to separate in a unitary manner the filter elements.