PURPOSE: To reduce intrusion of seawater into an operator's seat by integrally connecting at least an upper surface of a riseup part in a ship body side from the bow part of an upper hull to be tilted downward toward a position appearing in the peripheral edge of a ship body.

CONSTITUTION: In a synthetic resin vehicle 1, the sideward of a ship body 5 rises from a bow part of an upper bull 3, constituting a deck part, in order to provide a plower-like (wave plowing) function, and at least an upper surface B of this riseup part forms a slope so as to tilt downward toward a part appearing in the peripheral edge of the ship body 5. In this way, pouring seawater and lakewater in the deck part during advancing of the ship body 5, in the rearward movement, are removed to the outer by the upper surface B, tilting downward toward the outside, and an outer side surface C. Accordingly, a pouring amount of seawater and lakewater on a foot of an operator can be reduced, and an uncomfortable feeling can be reduced.