PURPOSE: To replace a cylindrical body with a new one by a simple manipulation, by enabling the cylindrical lock body to be removably fitted in a housing secured to a door or the like, and by providing a release manipulating part in the rear side of the door or the like.

CONSTITUTION: A housing 16 is secured to a door 17 or like, and a cylindrical lock body 14 is removably disposed in the housing 16 so as to constitute a cylindrical lock. Further, a release manipulating part 24 composed of a manipulating piece 64, a slide hole, a spring, a storage groove, an attaching piece or the like is provided in the housing 16 on the rear side of the door 17 or the like. Further, by manipulating the release manipulating part 24, the cylindrical lock body 14 is removed from the housing 16, and a new cylindrical lock body 14 is inserted into the housing 16.