To stabilize a posture of a plurality of occupants who are seated by facing a rear part of a hull by forming and protruding a protrusion bar over substantially whole width in a substantially central part in the forward and backward directions of a top face of a cross-sitting type seat on which the plurality of occupants are seated and forming a hold face which holds a waist of the occupant on a front face and a rear face of the protrusion bar.

A hull 2 of a water vehicle 1 is constituted in such a manner that a hull 3 and a deck 4 are connected by a gunnel 5 and that a cross-seating type seat device 9 is arranged on the deck 4. This seat device 9 is constituted by arranging a main seat 30 and a subseat 31 on a top face of the deck 4 in such a manner that they can be removed, respectively. In this case, a protrusion bar AS is formed and protrudes over the substantially whole width in a substantially central part in the forward and backward directions of the main seat 30 to divide the main seat 30 into a front seat part 30c and a rear seat part 30d by this protrusion bar 45. A hold face 45a which stops the slide in the backward direction of a driver is formed on a front face of the protrusion bar 45, and a hold face 45b which stops the slide in the forward direction of an occupant who is seated by facing the back of the hull 3 on the rear seat part 30d is formed on a rear face thereof.