To provide a binding-assisting instrument capable of binding simply and easily by only one string passing work and a binding string storing cartridge used for it.

The binding-assisting instrument consists of a base for mounting a binding object, a fixing member for fixing the mounted binding object and a string passing member equipped with a hook for hanging a binding string in the side of an end section. A grooved portion for inserting the above string passing member is formed in the diagonal line of 1 in the top face of the above base, a raised bottom section for forming a level difference with the top face of the base is formed in a pair in the diagonal side of the other which sandwiches the above grooved section.