A circuit breaker lockout apparatus, comprising a base body having a first section, a second section and a recess formed between the first and second sections (17, 19) for receiving a switch lever of a circuit breaker; a fixing element, in particular a locking screw, installed at the first section of the base body and having an actuation section to fix the base body to a switch lever of a circuit breaker received in the recess; and a cover adjustably fastened between a release position and a lockout position at the base body, wherein the actuation section of the fixing element is accessible in the release position and is covered in an inaccessible manner by the cover in the lockout position; wherein means (45, 47) are provided to fix the cover to the base body in the lockout position by means of a locking element (35, 37), in particular a hoop of a padlock, to block an adjustment of the cover from the lockout position into the release position; wherein the means (45, 47) comprise the base body having a projection at a side disposed opposite the recess, said projection of the base body engaging through a cutout formed in the cover from the inner cover side to the outer cover side in the lockout position, with the projection being provided at the outer cover side with at least one passage (49, 51) through which a locking element (35, 37) can be led; and wherein the at least one passage (49, 51) is oriented horizontally and/or vertically in a position of use of the circuit breaker lockout apparatus in which the first section of the base body is upwardly oriented, characterized in that the at least one passage (49, 51) comprises a first passage and a second passage, with the first passage and the second passage being the horizontal passage and the vertical passage, or vice versa. a base body having a first section, a second section and a recess formed between the first and second sections (17, 19) for receiving a switch lever of a circuit breaker; a fixing element, in particular a locking screw, installed at the first section of the base body and having an actuation section to fix the base body to a switch lever of a circuit breaker received in the recess; and a cover adjustably fastened between a release position and a lockout position at the base body, wherein the actuation section of the fixing element is accessible in the release position and is covered in an inaccessible manner by the cover in the lockout position; wherein means (45, 47) are provided to fix the cover to the base body in the lockout position by means of a locking element (35, 37), in particular a hoop of a padlock, to block an adjustment of the cover from the lockout position into the release position; wherein the means (45, 47) comprise the base body having a projection at a side disposed opposite the recess, said projection of the base body engaging through a cutout formed in the cover from the inner cover side to the outer cover side in the lockout position, with the projection being provided at the outer cover side with at least one passage (49, 51) through which a locking element (35, 37) can be led; and wherein the at least one passage (49, 51) is oriented horizontally and/or vertically in a position of use of the circuit breaker lockout apparatus in which the first section of the base body is upwardly oriented, characterized in that