Abstract: A rucksack including a bag and a shoulder straps/belt assembly laid out in the back of the bag. The bag is laid out in order to switch from a standard wearing position into a front position. The shoulder straps/belt assembly has two straps each having an upper portion, attached to the top of the back of the bag, an intermediate portion, and a lower portion. The ends common to the intermediate portions and to the lower portions are attached to the bottom of the back of the bag, the distal ends of the lower portions are provided with a fastening system. A sliding system is laid out on the bag in order to slidably mount one of the common ends between the intermediate portion and the lower portion of one of the straps. The strap has a fastening system laid out the common end between the upper portion and the intermediate portion.