Seat apparatus

A seat apparatus to be mounted on a vehicle, comprising:

• a seat cushion frame;
• a seat back frame which is arranged so as to stand from a back end part of the seat cushion frame;
• a cornering sensor which detects a cornering direction of the vehicle;
• and
• a control unit which controls the seat back frame on a basis of a detection result obtained by the cornering sensor,
• wherein the seat back frame includes:
• left and right side frames which are respectively arranged at two side parts of the seat back frame so as to extend in a vertical direction and which are connected to the seat cushion frame;
• a backboard which is arranged between the left and right side frames, the backboard including first and second side parts each extending in a width direction of the seat apparatus;
• and
• a swing mechanism which swings the backboard inside the left and right side frames with respect to a traveling direction of the vehicle, and
• wherein the control unit controls the swing mechanism so that, of the first and second side parts of the backboard, an inner side part which is inside with respect to the cornering direction is located backward comparing to an outer side part which is outside with respect to the cornering direction when the cornering direction of the vehicle is detected by the cornering sensor.