To provide a cylinder lock capable of being miniaturized in addition to the ensuring of the number of different keys set.

A rotor 13 is housed rotatably to a cylinder 14a for a rotor case 14. The first to fifth housing chambers 31 to 35 are formed so as to be arranged in the axial direction in the rotor 13. Two of the first to third plate tumblers 21 to 23 are housed so as to be arranged in the axial direction of the rotor 13 in each first to fifth housing chamber 31 to 35. Large-diametral recessed sections 43 and small-diametral recessed sections 44 capable of being engaged with unlocking projecting sections 72 for the first to third plate tumblers 21 to 23 are formed on the first straight line L1 and the second straight line L2 on each of the first surface 41 and the second surface 42 of a dimple key 12 in the dimple key 12. The recessed sections 43 and the recessed sections 44 on the first straight line L1 and the recessed sections 43 and the recessed sections 44 on the second straight line L2 are displaced and arranged in the longitudinal direction of the dimple key 12. Parts of the recessed sections 43 are disposed so as to cross over the center line M of the key 12 in the recessed sections 43.