Abstract: A kind of cylindrical lock, this lock able to be installed on a door, includes: one transmission structure which can operate a drive base, this drive base gearing a latch mechanism; this latch mechanism having: one tubular shaped element, which can be coupled to a handle for actuation; a tube, which can be rotated and inserted into the tubular shaped element; one pushing part, having one side with at least one pushing section, this pushing section able to push the drive base at the appropriate time; a collar, which can be set on one end of the tubular shaped element, a meshing section formed on one end of the collar; an engaging element, partly installed in this pushing part, one meshing section formed on this engaging element, and this engaging element having at least one pushable section; one rotating part, having at least one pushing portion, each pushing portion at the appropriate time pushing the adjacent pushable section of the engaging element; one lock set, having a lock core linked to one transmissio