To secure a relatively wide walk-in space by forward tilting a seat back by operating a single second operation lever without forward moving a seat cushion.

A seat 11 includes the seat cushion 12 and the seat back 13, a slide mechanism 14 slides the seat 11 in a cross direction and fixes it at a predetermined position, and a reclining mechanism 16 rotationally turns the seat back 13 in the cross direction of the seat cushion 12 and fixes it at a predetermined angle. A link mechanism 17 for connecting the seat 11 changeably into a use state and a folded state is provided between the seat 11 and the slide mechanism 14, the seat back 13 is forward tilted by operating a first operation lever and the seat cushion 12 is forward moved by a predetermined distance via the link mechanism 17. The seat back 13 is forward tilted while preventing the forward movement of the seat cushion 12 via the link mechanism by operating a second operation lever 32.