A locking mechanism for a collapsible ladder (1) comprising several ladder sections (5), each ladder section comprising two ladder bars (2, 3) arranged parallel to each other and interconnected at one end by a rung to form a U-shaped ladder section, and where each ladder section (5) is telescopically inserted into a lower ladder section to form a collapsible ladder (1), and where dampers (23) are provided at the lower end of the ladder bars (2, 3, and where the locking mechanism comprises retaining mechanisms (20, 41) provided on each ladder bar (2, 3), where a single pair of actuators of the locking mechanism can be arranged on any of the ladder sections (5) and still be able to collapse the entire ladder (1).