To provide a cylinder lock, which is difficult to unlock unjustly, particularly the cylinder lock, which is extremely difficult to unlock by a picking or the like.

The cylinder lock 10 is composed of a key 11 with a tabular inserting section (an inserting plate) 16 in which irregularities (a key crest section) 12A are formed and a cylinder 20 with a key inserting hole 21 in which the inserting section (the inserting plate) 16 of the key 11 is inserted, a pin hole 22 formed in response to the key inserting hole 21 and the pin 23 movably formed to the pin hole 22. A plurality of the inserting holes 21 under a mutually crossed state are formed. A plurality of the inserting sections (the inserting plates) 16 of the key 11 inserted into each key inserting hole 21 are formed.