In replication molding, the improvement of the transcription ratio of molded products generally increases resistance to cause various demolding defects. For this reason, the measurement of demolding resistance, clarification of demolding phenomena, and establishment of suitable demolding methods are important research themes. In this study, a mold for measuring demolding resistance when demolding molded products in the direction perpendicular to the transcribed surface was developed. On the stationary side of the mold base, a small load-cell is installed under the cavity block with a flange, which can measure the demolding resistance when the mold opens. By using this mechanism, we have successfully measured demolding resistances in fine pattern replication, rib-cavity molding, etc. This paper focuses on the replication process of L&S patterns and mirror-finished surface using a rectangular plate cavity. When molding plate products, the plate product must more or less be bended during ejection from the cavity and demolding. The bending deformation mode significantly influences measured data of demolding resistance in the direction perpendicular to the cavity surface. Due to such bending deformation of molded products, it has been very difficult to evaluate each influencing factor independently and quantitatively. To resolve this problem, we have developed a new two-step in-mold demolding system which prevents bending deformations of the molded products during the entire demolding process at the mold opening. It therefore enables the stable measurement of demolding resistance. Measurement experiments with this mold using L&S patterns clarified that the increase in the holding pressure level increases the demolding resistance peak due to improved transcription ratios, and that the change in the mold opening speed dramatically changes the demolding resistance with time. Furthermore, it was also found that the increase in the mold opening speed increases the vacuum pre