To provide a tumbler-type cylinder lock capable of being more safely managed than ever before.

This tumbler-type cylinder lock comprises: an outer cylinder 1; an inner cylinder 2 which includes a plurality of movable tumblers 3 and code maintaining mechanisms 4, 8 and 9; a state switching member 10 which switches between the set state of making a key code maintained by the code maintaining mechanisms depending on a rotational position with respect to the inner cylinder, and the reset state of allowing change of the key code; and connection switching mechanisms 13, 14 and 15 which switch among modes of rotational-direction connection between the outer and inner cylinders and the state switching member. In the insertion of a conversion key, the connection switching mechanisms allow the inner cylinder to rotate with respect to the outer cylinder, and fix the state switching member to the outer cylinder. In the insertion of a normal key, the connection switching mechanisms allow the inner cylinder and the state switching member to integrally rotate with respect to the outer cylinder in the set state, and fix the inner cylinder and the state switching member to the outer cylinder in the reset state.