Tool for turning inner spherical surface

A tool for turning an inner spherical surface comprises a rotary table, a first connecting rod, a second connecting rod and a knife rest which is fixed on a middle support plate. The rotary table is fixed on a tailstock through a rotary table seat, and the rotary table is fixed with a turning tool. The rotary table is hinged with the second connecting rod through the first connecting rod, the other end of the second connecting rod is hinged on the knife rest, and therefore the rotary table, the first connecting rod, the second connecting rod and the knife rest are enabled to form a crank slide block mechanism. The tool for turning the inner spherical surface has the advantages of effectively improving roughness of turning the inner spherical surface, and being good in working size stability, capable of controlling form and location tolerance easily and particularly suitable for volume production.