The invention provides a mechanical line spinning device. The mechanical line spinning device includes transmission wheels, transmission power boxes, transmission connection rods, fan-shaped tooth arms, adjustment rods, rocking rollers, sley swords, and a rack; the transmission power boxes are symmetrically arranged on two sides of the rack; the transmission wheels are arranged outside of the transmission power boxes; the transmission connection rods are linked with the fan-shaped tooth arms; the fan-shaped tooth arms are driven by the transmission wheels; the rocking rollers are arranged on inner sides of the fan-shaped tooth arms at the two sides; the adjustment rods are arranged on positions near the rack, at two sides of the rocking roller; a plurality of sley swords are evenly distributed on the rocking rollers; and the transmission power boxes are servo motor drive mechanisms. The advantages of the invention are that the mechanical line spinning device is simple in structure, is reasonable in design, can be flexibly adjusted, is easy to operate, is good in product quality, is high in transmission efficiency, is high in working efficiency, can save time and cost, and is suitable for large-scale line production.