Screwing/unscrewing tool suitable for a screw or a bolt that is difficult to access, in particular on a mast or a jib of a crane

A screwing/unscrewing tool, for screwing/unscrewing a screw or a bolt, the screwing/unscrewing tool comprising a first part and a second part coupled in rotation around a main axis, and comprising an adjustment screw, and wherein:

• the first part comprises a lever secured to a screwing/unscrewing bit provided with at least one screwing/unscrewing recess centered on the main axis;
• the second part comprises a support arm on which the screwing/unscrewing bit is rotatably mounted around the main axis, said support arm being equipped with a tapped hole;
• and
• the adjustment screw is screwed into the tapped hole, the adjustment screw having a coupling head configured for a coupling with a screw-gun or a wrench, and extended by a threaded rod having a free end suitable for abutment on the lever of the first part in order to apply a pivoting force to the lever around the main axis.