Abstract: An apparatus for preparing the edges of metal sheets to be welded comprises one or more metal working means, particularly milling cutters, included in a unit which is associated with means for producing between the sheet and the unit a relative movement during which the metal working means are working an edge of the sheet. The means for producing said relative movement comprise two sets each including at least three rotatable rollers which can be pressed against opposite sides of the sheet and of which two rollers engaging the same side of the sheet are spaced apart in the direction of movement in order, together with the roller or rollers engaging the opposite side of the sheet, to safely hold the sheet also when said metal working means have passed the end of the sheet edge being worked.