A locking device having a locking cylinder and a key. The locking cylinder includes a cylinder core with tumblers in a cylinder core, which is rotatably mounted in a cylinder housing. Standard coding for the key is produced by a step with longitudinal profiling on at least one flat side of the edge profile of the key, said step being associated with a counter step on the tumbler. In addition to the standard coding produced by step and counter step, the key has at least one set of beveled edge coding in a corner section of the edge profile. The beveled edged coding consists of recesses in the form of beveled cuts in the corresponding corner sections of the edge profile, relative to which are provided counter touching points in the corresponding tumbler. In a section of the key shaft, either the standard coding or beveled edge coding can optionally be used, thereby considerably increasing the diversity of the locking device while retaining the space-saving design.