ion (at a predetermined angle). [0094] (3) Tilt the seat face sloping down forward to be slightly slanted rearward. [0095] The angular correction is performed by controlling and operating known driving mechanisms, such as a electrical motor, a gear mechanism driven by an oil pressure jack, a wiring mechanism via pulleys, and a link mechanism, by an operational signal from the ECU 11. [0096]FIGS. 1