A test device for testing whether a coaxial accuracy between a test hole and a standard hole of an object is qualified or not includes a base to support the object, a fixing member to fix the object, and a positioning member and a testing member respectively mounted to a bottom and a top of the base. The positioning member includes a positioning pole to be inserted into a standard hole of the object. The testing member includes a testing pole slidably relative to and aligning with the positioning pole. A diameter of the testing pole is set to be equal to a standard diameter of a test hole subtracting a coaxial tolerance of the test hole. If the testing pole is capable of being inserted into the test hole, the coaxial accuracy between the test and standard holes of the object is qualified.