To solve a problem of an upper attaching clamp of a shoulder strap of a backpack that in order to produce efficient resilience, springs to apply inward resilience to connecting plates of the upper attaching clamp must be large because only one set of the springs are attached on the side of the outer surface of the connecting plates, so that the upper attaching clamp becomes large and too high to be attached to the backpack.

Connecting plates 4, 4 with attaching rings 3, 3 at the top are rotatably attached to the back of the backpack, so that the attaching rings 3, 3 can be oscillated. A set of springs 11, 11 to press the connecting plates 4, 4 inward are attached to the side of the outer surfaces 4b, 4b of the connecting plates 4, 4, and another set of springs 12, 12 to press the connecting plates 4, 4 inward are attached to spring inserting holes formed inside the connecting plates 4, 4. So the inward resilience is applied to the connecting plates 4, 4 by the two sets of springs 11 and 12.