A protection device (10) having a set (11) of protection
inflatable members (15, 20, 25) including left and right
inflatable lateral means (20, 25) that are suitable for co-operating respectively with the left and
right shoulder straps (6, 7), said device (10) possessing an inflator (30) for inflating said protection
inflatable members (15, 20, 25). The device includes a headrest (35) carrying a nape
airbag (15) of said set of inflatable members (15, 20, 25), the nape
airbag (15) including one passage (16, 17) per inflatable lateral means (20, 25) in order to convey fluid to each inflatable lateral means (20, 25), said headrest (35) being provided with a hollow support (40) carrying said inflator (30) and with a fluid
diffusion box (50) arranged in the nape
airbag (15) so as to convey a fluid from the inflator (30) to the nape airbag (15) and to the inflatable lateral means (20, 25).