A string-attached input pen including an input pen for a portable electronic device, and a string structural body, in which the string structural body has a first string section and a second string section, the first string section has a string-like member whose one end is coupled to the input pen and a ring member attached to the other end of the string-like member, and the second string section includes an annular belt, and the ring member is loosely inserted into the annular belt.