An apparatus for inspecting a collimator including a pigtail to which a fiber is connected to transmit an optical signal, a GRIN lens coaxially arranged with the pigtail, a glass tube accommodating and supporting the pigtail and the GRIN lens, and a metal sleeve protecting the glass tube, comprising an inspection table; a grip part provided on the inspection table, and gripping the collimator to be inspected; a first camera provided over the grip part having an axis perpendicular to a length of the collimator, and photographing the collimator along the length of the collimator; a second camera arranged coaxially with the collimator on the inspection table, and photographing the collimator perpendicular to an axis of the collimator; and a displaying part connected to the first and second camera, and displaying pictures transmitted from the first and second cameras. With this configuration, an apparatus for inspecting a collimator, which can effectively inspect the collimator, is provided, thereby increasing the reliability of the collimator.