A system comprising an air circuit breaker and an integrated interlock device installed at a cradle or a switchboard of the air circuit breaker to control an interaction with one or more other air circuit breakers, the air circuit breaker and the integrated interlock device comprising: a mounting plate installed at part of the cradle or the switchboard; a lever assembly rotatably installed at the mounting plate; and cables coupled to the lever assembly, each cable (81, 82, 83) including a sheath (81a, 82a, 83a) and a core member (81b, 82b, 83b), wherein the lever assembly includes: a bi-directional lever rotatably installed at the mounting plate, having a first arm and a second arm which are toward different directions and provided on a first rotation shaft, and moved in a connected state to a shaft lever of a circuit breaker body; and wherein the lever assembly further includes: a uni-directional lever rotatably installed at the mounting plate in a spaced state from the bi-directional lever, having a third arm which is toward one direction on the basis of a second rotation shaft, and moved in a connected state to an off lever of the circuit breaker body, wherein the off lever is configured to generate an interrupting operation to turn off the air circuit breaker, and wherein the cables include up to pairs of first to third cables (81, 82, 83) configured to transmit a mechanical force in a connected state to the first to third arms (41, 42, 53), respectively, and wherein each of the first to third arms (41, 42, 53) is provided with a pair of core holders (45, 46, 55) for fixing the pair of core members (81b, 82b, 83b) of the pair of first to third cables (81, 82, 83), wherein the pair of core holders (45, 46, 55) are installed on both side surfaces of each of the first to third arms (41, 42, 53). a mounting plate installed at part of the cradle or the switchboard; a lever assembly rotatably installed at the mounting plate; and cables coupled to the lever assembly, each cable (81, 82, 83) including a sheath (81a, 82a, 83a) and a core member (81b, 82b, 83b), wherein the lever assembly includes: a bi-directional lever rotatably installed at the mounting plate, having a first arm and a second arm which are toward different directions and provided on a first rotation shaft, and moved in a connected state to a shaft lever of a circuit breaker body; and wherein the lever assembly further includes: a uni-directional lever rotatably installed at the mounting plate in a spaced state from the bi-directional lever, having a third arm which is toward one direction on the basis of a second rotation shaft, and moved in a connected state to an off lever of the circuit breaker body, wherein the off lever is configured to generate an interrupting operation to turn off the air circuit breaker, and wherein the cables include up to pairs of first to third cables (81, 82, 83) configured to transmit a mechanical force in a connected state to the first to third arms (41, 42, 53), respectively, and wherein each of the first to third arms (41, 42, 53) is provided with a pair of core holders (45, 46, 55) for fixing the pair of core members (81b, 82b, 83b) of the pair of first to third cables (81, 82, 83), wherein the pair of core holders (45, 46, 55) are installed on both side surfaces of each of the first to third arms (41, 42, 53). a bi-directional lever rotatably installed at the mounting plate, having a first arm and a second arm which are toward different directions and provided on a first rotation shaft, and moved in a connected state to a shaft lever of a circuit breaker body; and wherein the lever assembly further includes: a uni-directional lever rotatably installed at the mounting plate in a spaced state from the bi-directional lever, having a third arm which is toward one direction on the basis of a second rotation shaft, and moved in a connected state to an off lever of the circuit breaker body, wherein the off lever is configured to generate an interrupting operation to turn off the air circuit breaker, and wherein the cables include up to pairs of first to third cables (81, 82, 83) configured to transmit a mechanical force in a connected state to the first to third arms (41, 42, 53), respectively, and wherein each of the first to third arms (41, 42, 53) is provided with a pair of core holders (45, 46, 55) for fixing the pair of core members (81b, 82b, 83b) of the pair of first to third cables (81, 82, 83), wherein the pair of core holders (45, 46, 55) are installed on both side surfaces of each of the first to third arms (41, 42, 53). a uni-directional lever rotatably installed at the mounting plate in a spaced state from the bi-directional lever, having a third arm which is toward one direction on the basis of a second rotation shaft, and moved in a connected state to an off lever of the circuit breaker body, wherein the off lever is configured to generate an interrupting operation to turn off the air circuit breaker, and wherein the cables include up to pairs of first to third cables (81, 82, 83) configured to transmit a mechanical force in a connected state to the first to third arms (41, 42, 53), respectively, and wherein each of the first to third arms (41, 42, 53) is provided with a pair of core holders (45, 46, 55) for fixing the pair of core members (81b, 82b, 83b) of the pair of first to third cables (81, 82, 83), wherein the pair of core holders (45, 46, 55) are installed on both side surfaces of each of the first to third arms (41, 42, 53).