This study describes 3D X-ray laminography using a projection method for reconstruction of arbitrary cross-sectional images. The X-ray inspection images acquired from a single focal plane include information of the other focal planes as well. Hence projection images of the other focal planes can be obtained by the geometric projection method for arbitrary height and angle. This paper provides the reconstruction methods of arbitrary cross-sectional image for parallel and cone-beam X-ray and visualization of the object in three dimensions using 3D laminography. 2D arbitrary projection images for the other focal planes were obtained by deriving the geometric projection formulae for arbitrary height and angle images. After arbitrary cross-sectional images had been reconstructed by 2D laminography using projection image sets of all focal planes, 3D laminography was realized so that the object of ball grid array package was three-dimensionally visualized. For demonstrating 3D NDT (Non-destruction testing) method, we developed laminography system with CMOS image sensor. Finally, it was shown by experimental results that 3D laminography of object could be reconstructed correctly by the geometric projection method.