X-ray CT system for industrial inspection has some problems when it inspects flat objects. The problems are expansion rate and contrast. We previously implemented an oblique X-ray CT system, and found those problems were almost solved and mat vertical accuracy was comparatively low. We now intend to improve the vertical accuracy by implementing extra two-arc cone-beam X-ray scan. The two-arc scan is for compensating the lack of data from the conventional oblique scan. The overall reconstruction algorithm is based on inverse Radon transform and Grangeat's formula. In order to evaluate the accuracy of reconstructed images quantitatively, the computer simulation using a BGA phantom was implemented. Through the study it was revealed that the proposed method can compensate the previous reconstruction accuracy, and that proper distribution from both oblique scan and two-arc scan is needed for the correct reconstruction.