The present invention provides a mechanical interlocking device. The device comprises a pull rod with teeth, a cylindrical bearing seat, a screw, a gear, connecting boards, an I-shaped connecting piece, a movable rod, a rotating shaft, a connecting rod, a worm I, a lock cylinder, a worm II and a worm gear. The screw is disposed in the middle at the upper end of the gear. The screw is provided with the cylindrical bearing seat. The front end of the gear is provided with the pull rod with teeth. Due to the design, the isolation switch can be turned on and off. The connecting boards are symmetrically fixed on the right end of the I-shaped connecting piece. The front end of the I-shaped connecting piece is provided with the movable rod. Two connecting boards are assembled on the upper end and the lower end of the rotating shaft. The mechanical interlocking device is simple in structure and design and has a linkage function. The left end of the connecting rod is provided with the worm I, the lower end of the worm I is provided with the worm gear, the lower end of the worm gear is provided with the worm II, and the left end of the worm II is provided with the lock cylinder. Due to the design, a cabinet and the pull rod with teeth can work simultaneously, so that the labor intensity is lowered. The mechanical interlocking device is convenient to use, has a long service life, can help reduce the cost of the device, and is highly reliable.