The present invention provides a separating tool for separating a multi-core ribbon fiber (1) obtained by arranging a plurality of optical fibers (1a) in a plane and integrating the fibers with a common coating (1b) into single-core optical fibers, and includes a fiber accommodating means for accommodating the multi-core ribbon fiber (1) in an accommodating area (2), a fiber holding means for holding the multi-core ribbon fiber (1) in the accommodating area (2), a scratching means (3) for forming a scratch on a surface of a common coating (1b) of the multi-core ribbon fiber (1) held by the fiber holding means, an arrangement defining means (4) for changing an pitch position of the scratching means (3), and a shearing force applying means (5) for applying a shearing force to the multi-core ribbon fiber (1) along the scratch formed by the scratching means (3).