The utility model relates to a cylindrical lock body, particularly the design which can make a positioning component set of the lock body form a stable positioning state in order to make a transmission component set be avoided from being destroyed. The utility model utilizing a positioning shell seat which covers an inner sleeve seat, a containing chamber and an outer sleeve seat and positioning bolts which penetrate through the positioning shell seat, the inner sleeve seat, the containing chamber and the outer sleeve seat and is clamped at the place of an outer sleeve ring in bulging, makes the positioning component set keep an excellent positioning state due to the stable states among the outer sleeve ring, an inner sleeve ring and a door plate. Thus, the damage of the internal components caused by improper external force which is exerted on the place of a handle and unstable positioning component set is avoided. The utility model provides a lock body structure with more favorable stableness.