Headrest device

A headrest device includes a headrest (2) provided over a seatback of a seat, a sliding means (3) for slidably adjusting the seat in back and forth directions, a position-adjusting means (6) for adjusting position of the headrest, and a connecting mechanism (5) connecting the sliding means and the position-adjusting means. The connecting mechanism operates the position-adjusting means in conjunction with operation of the sliding means. The connecting mechanism moves in a first direction when the sliding means moves forward, and the connecting mechanism moves in a second direction when the sliding means moves backward.