The present invention relates to an antibody specifically binding to human growth arrest specific 6 (hGas6). Specifically, the present invention relates to a monoclonal antibody or an antibody fragment thereof which binds to at least one of amino acid residues at positions 314, 315, and 316 of human Gas6, a nucleic acid comprising a nucleotide sequence encoding the antibody or the antibody fragment, a transformed cell comprising a vector comprising the nucleic acid, a method for producing the antibody or the antibody fragment, a reagent for detection or assay of Gas6, comprising the antibody or the antibody fragment, a therapeutic agent or a diagnostic agent for a Gas6-related disease, comprising the antibody or the antibody fragment as an active ingredient, and use of the antibody or the antibody fragment for the production of a therapeutic agent or a diagnostic agent for a Gas6-related disease.