A locking device for a telescoping pole for use with a retractable handle system, the pole having at least one moveable section slideably mounted in a guide member having at least one opening. The locking device includes a body fixed to the movable section, a locking member carried by the body and movable between locking an unlocking positions, a rotatable lever carried by the body and pivotable between a release position, in which relative movement is permitted between the movable section and the guide member, and a blocking position, in which the lever comes to bear on the guide member and exerts a force assuring a transverse immobilization of the moveable section in the guide member. The lever is coupled to the locking member to be displaced toward the blocking position when the locking member is engaged in the opening under the force produced by a restoring element.