Abstract: A tube straightness checking apparatus includes a gauging mechanism disposed along a linear path and being operable to check the straightness of the tube as it is moved along the path past the mechanism. The gauging mechanism is operable to detect deviation of the tube from an imaginary centerline which is generally coincident with the linear path. The apparatus also includes linear hearing sets which guide a tube along the generally linear path past the gauging mechanism. Two embodiments of the gauging mechanism are disclosed. In the preferred embodiment, the gauging mechanism includes a gauge plate with a circular gauging orifice defined therein through which the tube passes as it is moved along the linear path. The gauge plate is electrically conductive and forms part of an electric circuit which is operable to provide an indication of an out-of-straightness condition upon the tube contacting the gauge plate as the tube moves along the linear path through the gauging orifice of the plate.