Structure of an adjusting buckle for shoulder straps

A structure of an adjusting buckle for a shoulder strap comprises an integrally formed adjusting buckle body and a press-release button, wherein said adjustable buckle body has a centerline, two inner slots are disposed to each side of the centerline and two outer slots are disposed on each side of said inner slots opposite to said centerline, said press-release button has a bottom formed with two protuberances configured and positioned to engage said two outer slots, sand said shoulder strap is made of silicone and passes through said two inner slots, whereby when said press-release button is engaged with said adjustable buckle body, said shoulder strap will be kept in a firm position by having the press-release button frictionally engaging the shoulder trap that passes through the inner slots.