The invention relates to a backpack including a main rear pocket adapted to receive a load and carrying straps configured to position and maintain the main rear pocket on the user's shoulders, whereby the main rear pocket is formed by the juncture of a first base panel, made of flexible material, adapted to be in contact with the body of the user, and of a second external panel, also made of flexible material, the first base panel being extended at the ends of the main rear pocket to form two closed side loops for passage of the user's arms, forming the carrying straps.