A high-stability miniature circuit breaker includes an operating mechanism, wherein a pivotal shaft of the operating mechanism fixed on a shell includes a first shaft section, a second shaft section and a shaft shoulder; the diameter of the second shaft section is larger than that of the first shaft section, and the diameter of the shaft shoulder is larger than that of the second shaft section. A lever is installed on the first shaft section through a first shaft hole in a pivoting way and used for limiting the axial position of a protruding mesa relative to the pivotal shaft through contact fit between the protruding mesa disposed on the lever and a thrust surface on the second shaft section. A latch assembly is installed on the second shaft section through a second shaft hole in a pivoting way; a first end face fitted with a support surface on the shaft shoulder is disposed at one end of the second shaft hole; and a second end face fitted with the protruding mesa is disposed at the other end of the second shaft hole. A first hasp fitted with a second hasp of the latch assembly is disposed on a connecting rod, the connecting rod is engaged with each other with the latch assembly in the first and second hasp contact and withhold state, and the latch assembly controls a drive rod and the lever not to move relatively; the connecting rod is separated from the latch assembly when the first and second hasps are separated and unbuckled, and the latch assembly is separated from the drive rod, so that the drive rod can slide along a groove of the lever.
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