Abstract: The invention relates to an adjusting device for a motor vehicle seat with a first adjusting arm (20), with a second adjusting arm (22) that is arranged opposite the first adjusting arm (20) so as to be rotatable about an axle (24), with a drive shaft (32) allocated to the first adjusting arm (20) that has a free end and carries a pinion (36), and with a toothed quadrant (38) formed in the second adjusting arm (22) and meshing with the pinion (36). A supporting part (44) is formed on the second adjusting arm (22), wherein said supporting part (44) is located in the vicinity of the drive shaft (32), is positioned near the drive shaft (32) radially outside thereof when the pinion (36) is subjected to normal load and gets in contact with the drive shaft (32) and supports it when the pinion (36) is subjected to heavy load, particularly when the pinion (36) is subjected to a load occasioned by an accident.