To improve safety, comfortableness of riding of passenger while securing free passing without generating a narrow position in a passage, and to save the labor of occupant by providing a floor plate passing through a pair of vertical passing members in right and left and connected to a lower end of a stairs for communicating a floor room and an underfloor room with each other and extended in the fore and aft direction, and providing the floor room with a vertical passage for underfloor room having a projecting raising top plate.

A passenger moves in a passage Y on foot 25, and places a compact luggage on a luggage shelf 7 and seats 26 on a reserved seat B. When a large luggage is necessary, the passenger passes through the passage Y and a stairs 6 for underfloor room and walks in a through vertical passage 8 in the stooping condition and arrives a trunk 11 provided in a vehicle, and takes out the large luggage. At the time of reciprocating between each seat B and a rear part of a chamber 3, each right and left passage Y is used as one-way only for forward movement and backward movement for circulation, and the passengers can move without passing each other in the passage Y, and the occupants similarly move. With this structure that the passenger can freely pass through the passenger room, an occupant room 5 for take-a-nap and the trunk 4 provided in a vehicle and that a narrow position is not formed in the passage inside of the passenger room, safety, comfortableness of riding and responsiveness of passenger are improved, and labor of occupant can be saved.