Abstract: A roll bar for convertible-type vehicles includes a generally U-shaped inverted roll bar structure pivotally mounted to an automobile chassis for extending across and above the passenger compartment when in the up position and pivotally mounted to pivot to a downward generally horizontal retracted position. The roll bar is mounted to pivot generally about a support bar that is mounted within and extends to each side of the chassis and includes a fixed gear on the mounting bar and a driving gear carried by the roll bar in driving engagement with the fixed gear with a curved guide slot disposed adjacent the drive mechanism for guiding the roll bar into the respective vertical and horizontal positions.