Abstract: A door lock comprises a bolt and a mechanism for moving the bolt between a protruding locking position and a withdrawn unlocking position. The bolt is provided, in its protruding part, with at least one auxiliary locking element, such as a ball, a pin or the like, movable in a transverse duct in the bolt between a first position, in which it partly extends outside the sides of the bolt, and a second retracted position. In the bolt, there is also an operating member moving in the longitudinal direction of the bolt. This member is arranged to move each auxiliary locking element into its first position, when the bolt reaches its protruding position. Preferably, the bolt is provided with two auxiliary locking elements moving symmetrically with regard to a longitudinal plane of the bolt.