Abstract: A seat apparatus includes a seat cushion on which an operator is seated, a seatback supporting the operator seated on the seat cushion, the seatback being configured to incline forward to reduce an angle of the seatback relative to the seat cushion and to incline rearward to increase the angle of the seatback relative to the seat cushion, a seatback drive device inclining the seatback forward and rearward relative to the seat cushion, a seatback operating switch provided at a position where is reached by the operator seated on the seat cushion, the seatback operating switch operating the seatback driving device in response to an operation of the switch, and an excessive load restricting device restricting an excessive load applied to the operator seated on the seat cushion by limiting a forward inclination of the seatback when the seatback operating switch is operated so as to incline the seatback forward.