PURPOSE: To improve convenience of a commodity against a storage case of a seated driver while smoothly carrying out handling of the commodity stored in the storage case by devising the storage case to appear on the back surface side of a movable part free to take out or store the commodity only by inclining motion of the movable part by the seated driver.

CONSTITUTION: A seat back part 4c of a seat back 4 is formed on a movable part free to incline forward with a floor panel 2 as its supporting point, and on the back surface side of the seat back part 4c, a storage case 11 capable of storing a commodity is provided. The storage case 11 is supported free to revolve its side surface lower end part front end position on the seat back part 4c and its side surface lower end part rear end position on the floor panel 2 through a link member 15 so that storage position of the commodity is maintained on the back surface side of the seat back part 4c in either state of the inclining and erecting states of the seat back part 4c.