ENERGY ABORBING STRUCTURE OF VEHICLE SIDE PART

PROBLEM TO BE SOLVED: To expand an air bag stably in any sliding position of a seat while protecting an occupant effectively by making the distance between a sliding rail and the shelf face line of an arm rest the same or gradually smaller toward the front side of the seat. SOLUTION: When a side collision to the left side part of an automobile is detected by an acceleration sensor, an inflator is ignited by an ignition signal so as to supply a large quantity of gas to an air bag 24, and a chest protective part is first expanded between the chest of an occupant and a side door 40 frontward of the left part of a seat back 3. At this time, the lower end line of the chest protective part is expanded frontward along a shelf face 41a of an arm rest 41 so as to protect the chest of the occupant. Since the shelf face 41a of the arm rest 41 is inclined upward to the front parallelly with each sliding rail 8, the vertical position relation between the shelf face 41a and the lower end face of the air bag 24 does not change in any sliding position of a seat l. As a result, the air bag 24 is stably expanded regardless of the sliding position of the seat 1 while protecting the occupant effectively.