PURPOSE: To reduce a load working upon the rear part of a vehicle body and make effective use of the rear part of a cabin.

CONSTITUTION: A rearmost long sideways seat 9 is disposed on a tiered platform 8 with its side ends 9a, 9a separated from cabin side walls 3, 4 by a dimension (a) roughly equivalent to allowable width for one occupant to seat himself or greater respectively to reduce the number of occupants who can seat themselves on the long sideways seat, and reduce the load working upon the rear part of a vehicle body, and spaces on the tiered platform 8 between both the ends 9a, 9a of the seat and the cabin side walls 3, 4 is formed so as to be used as spaces 10, 10 for placing loads.