In this study, we developed a highly sensitive and flexible contact pressure sensor by transferring an ultrathin piezoresistive silicon membrane to a flexible substrate. The sensor consists of two sensors, a contact pressure sensor and a strain sensor for strain compensation. From the output of these two sensors, strain caused by fixing the sensor to the curved surface can be compensated for, so that we can accurately measure contact pressure. In the experiments, we confirmed that the fabricated contact pressure sensor has the same sensitivity on both a flat surface and a curved surface. We also confirmed that our sensor can correctly measure contact pressure by compensating for the distortion when fixed to a curved surface.