A fall arrest system adapted to prevent falls while climbing structures. An MPEG video decoder reads out this recoded data sequence in a reverse time-series manner and decodes it successively, and then converts it to a video signal so as to be outputted to a display. The reaction vessel includes a flexible wall portion that is adjacent to a perforator that can puncture a membrane separating the lime and water. A front end of the buttocks part stretching unit is positioned more backward than a center of the longitudinal direction of the leg opening unit. The suspension polymerization process enables vinyl polymer beads having a narrow bead size distribution to be produced efficiently due to the use of the slurry.