This study comparatively investigated the functional properties, chemical compositions, and morphological characters of soluble dietary fibers (SDFs) from the root, stem, and leaf of Angelica keiskei. The SDFs showed relevant functional properties, with the root SDF (RSDF) exhibiting the highest water-holding capacity (22.6 g/g), oil-holding capacity (6.29 mL/g), swelling capacity (36.6 mL/g), emulsion stability, and fat adsorption (5.66 g/g). Stem SDF (SSDF) gave the highest foam stability, toxic ions adsorption (Pb: 1.12 mg/g; As: 3.22 mg/g), and bile acid salts adsorption (sodium cholate: 85.6 mg/g; sodium glycocholate: 93.1 mg/g; sodium taurocholate: 125.7 mg/g). RSDF and SSDF presented similar monosaccharide compositions, thermal property, chemical bonds and groups, and irregular, rough, and porous surfaces. It can be concluded that the obtained SDFs, especially for RSDF and SSDF, can be used in the food industry as fiber-rich functional ingredients.