To provide a cylinder lock device with a constitution can suppress an unauthorized unlocking operation.

This cylinder lock device includes: a rotor case 20 which has engaging groove portions 20b and 20d as first and second engaging portions on a cylindrical inside; a rotor 30 which is turnably arranged inside the rotor case 20, and in which a key insertion hole is formed in such a shape as to be elongated in an axial direction; and a plurality of tumblers 40 which are provided in such a manner as to be freely movable in the radial direction of the rotor 30, which are urged to a radial outside and engaged with the engaging groove portion of the rotor case 20, and which are disengaged from the rotor case 20 by being disengaged with the engaging groove portion 20b when a normal key is inserted into the key insertion hole. In the rotor case 20, the engaging groove portion 20b is provided in a LOCK position, and the engaging groove portion 20d is provided in a position except the LOCK position.