RECLINING DEVICE AND VEHICLE SEAT

In a reclining device, a lock mechanism locks tilting of a seat back. A knob is connected to a connecting cylinder, and in a case in which the knob is operated, the connecting cylinder is rotated, and a lock mechanism unlocks tilting of the seat back. At a time of a side collision of a vehicle, an impact load is input to the knob, and the knob is disconnected from the connecting cylinder. Therefore, even in a case in which the knob is operated by an impact load, the rotation of the connecting cylinder can be suppressed, and the unlocking of the tilting of the seat back can be suppressed.