To make the most of both the spaces of a cabin and a stern deck behind the cabin for a small marine vessel.

This cabin structure for a small marine vessel is so constituted that a cabin 11 is formed roughly at the center of its hull, a stern deck 13 is formed at the rear side of the cabin, an opening part 2 for passengers to go in/out, is formed at the center part of the rear wall of the cabin 11, and the opening part 2 is closed by revolving doors 3 and 4 each of which is revolved around each corner close to the insides of both its side parts, and is opened so as to be positioned at the vessel side parts in the front end of the stern deck 13.