PURPOSE: To obviate the need of a supporting pillar on a public room deck and facilitate the designing of a public room, etc. by suspension-supporting a deck which is directly over the public room deck on the left and right longitudinal passing walls in pair over the front and rear lateral partitioning walls through a plurality of suspended pillars which are directly over the upper deck.

CONSTITUTION: A plurality of suspended pillars 1 which transmit the load of a cabin deck 02 which is directly over a public room deck 01 to a longitudinal passing wall 2 through an exposed deck 04 which is directly over the cabin deck 02 are installed, and the longitudinal and lateral positions are set along a supporting pillar 03 in the below. The left and right longitudinal passing walls 2 in pair are longitudinally installed on the exposed deck 04 in correspon dence with the lateral position of the suspended pillar 1 which is directly above, and the longitudinal edge is extended to the longitudinal position at least of a lateral partitioning wall 05 in the front and rear parts. Accordingly, the weight of the cabin deck 02 as the deck directly over the public room deck 01 is suspension-supported through the suspended pillar 1 by the longitudinal passing wall 2 over the exposed deck 04, and the need of the supporting pillar on the public room deck 01 is obviated.