Abstract: A locking device for locking the trailing wheels of a wheeled carriage, particularly of a perambulator, in the straight running position, the trailing wheels being mounted for pivotal movement about an upright axis extending perpendicular to their axis of rotation without intersecting it, wherein a support member carrying the axis of rotation of the trailing wheel is connected to a vertically extending sleeve mounted for rotation about its vertical axis in a concentrically surrounding cylindrical recess in the wheeled carriage, and wherein a resiliently deformable plug extends through the sleeve from above, the plug having a disk-shaped enlarged head portion engaging the rim of the upper end face of the recess and being in positive locking engagement with the sleeve so that the plug is non-rotatably connected therewith, the locking device including a substantially vertically extending engagement surface formed on the disk-shaped head portion for positive locking engagement with a locking member pivotally moun