Estimation of the disk load in order to prevent low back pain is useful. However, the conventional methods of measuring disc load are invasive and their use is limited due to measurement environments. This study proposes a new method of estimating the lumbar disc load to measure curvature of the lumbar portion and to estimate the lumbar disc load safely using a bending sensor. The radius curvature can be measured relatively easily and without damaging the body by using this method. The bending sensors are attached along vertebra end of five vertebras and the curvature of the lumbar portion is estimated by reading the change in output voltage. The lumbar disk load with static posture was estimated by proposed method. The result shows the same tendency as the previous method. The proposed method has a possibility of developing a new system using the biofeedback based on the lumbar disc load.