SEAT DEVICE

There is provided a seat device that can appropriately detect seating in a simpler configuration even though a seating position is changed in the longitudinal direction. A seat device (1) according to the present invention includes a cushion pad (3) and a pressure sensitive switch (SW1) that detects a load applied from the seating face of the cushion pad (3). A groove (50) extending in the longitudinal direction of the cushion pad (3) is formed on the lower face of the cushion pad (3) of the seat device (1), and the pressure sensitive switch (SW1) is disposed in the space of the groove (50).