To effectively utilize both the spaces of a cabin and a stern deck on the rear side of the cabin of a small ship.

A cabin 3, a stern deck 4, and an opening part for making a person accessible are formed on nearly the central part of a hull, on the rear side of the cabin 3, and on the center part of the rear wall of the cabin 3 respectively, and the opening part is closed by a rotation door 51 rotating, with a hinge fitting part on one side part as a center, to be opened so as to be along the ship side part of the stern deck 4, and a slide door 52 opened by adjoining the door 51 to slide in the direction reverse to the rotation door. Also, seats 41 and 42 and a seat 35 are provided on both the ship side parts of the stern deck 4, and in the fore side cabin 3 of the rear wall respectively, and both the ship sides and the rear part of the stern deck 4 are surrounded by a gunnel to form the seat back 44 of the seat by the inner side surface of the gunnel.