We aim at employing a reflection type tactile sensor as sensors of robot fingers. The sensor measures deformation of its contact surface by capturing reflection images and solving an inverse problem. In order to solve it, we formulate a new method of shape reconstruction expanding to three dimensional surface deformation. We evaluated our proposed method by reconstructing the deformed surface from reflection images produced by simulation. The result shows that our proposed method correctly estimates locations where deformation occurs, and about magnitude of deformation, some errors occur.