The invention relates to a device (60) for aligning sheets (6), especially sheets made from paper, cardboards or paperboard. The device comprises an alignment device (61) and drive (63) associated with the alignment device (61), wherein the alignment device (61) is movable in the circumferential (U), side (S) and oblique (D) directions, used for aligning a sheet (6) in the circumferential (U), side (S) and oblique (D) directions, and provided with at least one holding member for holding said sheet (6); and the drive (63) is used for enabling the alignment device (61) to move in the circumferential (U), side (S) and oblique (D) directions. According to the invention, at least a two-part articulated arm (64) is provided for supporting the alignment device (61). Advantageously, the device (60) allows a simple, low-cost and high-durability supporting.