PURPOSE: To manufacture a cylinder lock, in which a cylinder lock in the cylinder lock used by a user can be exchanged quickly and malfeasant release (picking) can be prevented while a key inserting port, into which a key is inserted, in a rotor is located at a position nearer to the peripheral section side of the rotor than the center of the rotor, in structure, in which an exchanging function is simplified.

CONSTITUTION: A key inserting port in a rotor is put and formed to a section nearer to the peripheral section 20 side than the center of the rotor 10. A rotary member 30 is engaged into an annular recessed groove 14 formed on the front end 11 side of the rotor 10. When the rotary member 30 is positioned in a locus, on which a key K is rotated, and the key K is moved forward along a key inserting groove 13, the side edge section 21 of the key K is pushed against a spring 50 while being abutted against the rotary member with the revolution of the key K, thus releasing the engagement of the rotary member 30 and the rotor 10, then allowing the extraction of the rotor 10 together with the key K.