Provided is an antibody specifically binding to the CTLD (C-type lectin like domain) of clec14a (C-type lectin domain family 14, member A), a method for preparing the antibody, a composition for suppressing angiogenesis comprising the antibody, a method for suppressing angiogenesis by administering the antibody or the composition, a composition for preventing or treating cancer comprising the antibody, a method for treating cancer by administering the antibody or the composition, a composition for diagnosing cancer comprising the antibody, a kit for diagnosing cancer comprising the composition, a method for diagnosing cancer using the composition, a composition for suppressing angiogenesis comprising a material for inhibiting expression of clec14a, a kit for angiogenesis comprising the composition, a method for suppressing angiogenesis or treating cancer using the composition, and the use of the CTLD of clec14a as an epitope for an antibody suppressive of angiogenesis.