PURPOSE: To prevent abrasion and damage to a knapsack and school things and to exert no undersirable influence on the body of school children carrying the knapsack on his back by softening a shock between the inner wall surface of the knapsack main body and the school things.

CONSTITUTION: A knapscak main body 1 is formed by sewing up the front edge of a base plate 6 and the front edges of right and left large gores 3, 4 integrally connected to the right and left of the base plate 6, and the base edge of a large partition plate 5 and the right and left side edges, respectively, and sewing up the base plate 6 and the respective rear edges of the right and left large gores 3, 4, and the base edge of a back plate 2 and the right and left side edges, respectively. A buffer member 9 is fixed to at least one of the back plate 2, the left large gore 3, the right large gore 4 and the large partition plate 5.