A novel linker compound that minimizes any nonspecific hydrophobic interactions and is capable of easily regulating the length to disulfide group subjected to metal bond to thereby enable efficient formation of metal-sulfur bond; a novel ligand complex or ligand carrying substance; and a process for producing them. There is provided a linker compound comprising the structure of the general formula: (1) (wherein each of a, b, d and e independently is an integer of 0 to 6). The above X at a molecular end has an aromatic amino group and at its main chain has a structure of multi-branched structural site composed of 3 or more hydrocarbon-derived chains optionally having carbon-nitrogen bonds. The ligand complex consists of the above linker compound having a sugar molecule introduced therein.