To provide a cylinder lock, giving a sense of a click even in the case of using only a tumbler for a key distinction structure.

This cylinder lock includes a suitable number of tumblers, which moves a rotary boundary 3 between a plug 1 and a cylinder case 2 rotatably holding the plug 1 to a border to open and close the rotary boundary 3, and are energized to the rotary boundary 3 closed position by a compression spring 4, and driven to the rotary boundary 3 opened position by insertion of an authentic unlocking key 5. The suitable number of tumblers 6 are mounted with one end projecting into the rotary boundary 3 to be retreated to the rotary boundary 3 opened position by turning operation to the plug 1 in the insertion state of the authentic unlocking key 5, whereby resisting force is applied to the turning operation from the initial rotational position.