The invention relates to an apparatus for inserting a cage between vertebrae, according to the inventive concept, includes a body accommodating an inner rod coupled to the cage, which is to be inserted between vertebrae, a push bar installed in the body to be slid and configured to push one side of the cage as the push bar is moved forwards from the body, a support bar supporting an opposite side of the cage and installed in the body to be slid to move rearwards when the push bar is moved forwards, and an adjustment unit installed in the body to be manipulated and configured to adjust movements of the push bar and the support bar such that a rotation amount of the cage is adjusted according to manipulation by a user.