The utility model discloses a mechanical linkage circuit breaker, comprising a crossbeam. The crossbeam is provided with a link mechanism for driving the moving contact of the breaker body to move up and down; the link mechanism comprises three crank arms arranged on the crossbeam in a rotation manner and connecting rods respectively hinged to each crank arm; adjacent two crank arms and connecting rods between the two crank arms comprise a parallel four-link mechanism; each connecting rod possesses an end installing hole for the pin positioned at the end portion to penetrate and an intermediate installing hole for the pin positioned at the middle portion to penetrate; the end installing hole is a circular hole; and the intermediate installing hole is a long hole extended up and down. The pin is cooperated with the corresponding connecting rod through the long hole, with the structure of the long hole, even when an assembling tolerance is accumulated to a large value, and when an interelectrode pull bar is bended slightly, installation can be carried out reliably and conveniently, and simultaneously, the directions of active force of crank arms with pins and long holes are always parallel with the axes of the connection rods, and thereby the transmission efficiency of connecting rods is raised.