In the line heating process, only angular distortion whose direction is perpendicular to that of a heating path is expected. However, it is observed that a deformation is induced in the direction of the heating line. Because of this, during forming a saddle type plate we experience unfavorable deformations in the unintended direction. In this paper we discuss the unwanted distortion in the manufacturing process by analyzing intermediate plates of saddle type during fabrication. For this analysis we consider the longitudinal and transversal directions separately and use the bending strain for the analysis.