To make the thickness of a bulwark uniformed throughout, by installing a handrail on an upper face side of at least a part of the bulwark which is adjacent to a floor panel of a front side of a seat, separately from the bulwark.

In each side part of a boat 1, an intermediate part in a longitudinal direction, of a hull 3 as a part of a bulwark 14, and the seats 24, 29 installed at an upper part of the side part of a floor panel 13, and an intermediate part floor panel 36 as a part of the front side floor panel 13 of these seats 24, 29, are adjacent to each other in a width direction of the hull 3. A handrail 39 is installed on an upper face side of a part of the bulwark 14 adjacent to the seats 24, 29 and the intermediate part floor panel 36, separately from the bulwark 14, and the handrail 36 is formed by a stainless metallic pipe material extending in the longitudinal direction.