To increase further the capacity of a container space in a hull, and suppress the intrusion of the water into the inside of the hull through a container device, by securing the hull with sufficient strength and ridigity, even when the capacity of the container space is increased.

A housing container 51 opened upward is provided inside a hull 3. The space in this housing container 51 is made in a container space 52. While a container opening 53 to communicate the outer side of the deck 5 of the hull 3 and the above container space 52 to each other is provided, a lid body 55 to close the container opening 53 in a free opening/closing manner is provided. The container opening 53 is formed on the deck 5. When the hull 3 is observed in the longitudinal cross section, the width size W at the upper end of the container space 52 is made larger than the width size w of the container opening 53. The housing container 51 is formed integrally on the deck 5.