To provide an apparatus for passing a string by which the string can be passed, in a short time and accurately, through a bag such as a purse.

When a bag body 20 is mounted on a straight-through means 3 and 4, a string through-hole 20c of the bag body 20 is arranged in parallel and is made straightly through and a passage for making needle members 8 and 9 pass through is ensured. After the passage for making the needle members 8 and 9 pass through is ensured, inlets 20f and 20f for the string through-hole are expanded by inlet expanding means 7a and 7b to make insertion of the needle members 8 and 9 possible. When the needle members 8 and 9 are moved through passing-through means 14, 15 and 16 under this condition, the needle members 8 and 9 go straightly in the string through-hole 20c and when the apex parts of the needle members are forwarded from an outlet 20f', the string passes through the string through-hole 20c to pass the string through.