PURPOSE: To realize a shock absorbing guard barrier for a motor course, a cycle track, a ski track or a course for any one of them by jointing a plurality of sheets, made of plastic formed in relief, to form a packet.

CONSTITUTION: A packet is formed by jointing a plurality of sheets made of plastic such as PVC with appropriate thickness or similar material. These sheets are formed by pressing under vacuum using a means with a series of corrugation or unevenness so as to form specific height H larger than the thickness of a plastic sheet. Such sheets are placed one on top of another so that the protruding parts face the recessed parts to form a small mattress of appropriate thickness, thus realizing a shock absorbing guard barrier for a motor course, a cycle track, a ski track or a course for any one of them.