Abstract: An improved lens grinding apparatus of the type including a grinding wheel for grinding lens blank, a wheel shaft for mounting the grinding wheel and two lens shafts adapted to rotatably clamp lens blank therebetween. The apparatus further includes a writing device for scribing a band of magnetized zone on the magnetic sheet by means of a writing magnet on the free end of the first arm, a reading device for reading the contour line of the magnetized zone by means of hole elements on the second arm and a center distance changing device for changing the center distance between the wheel shaft and the lens shafts in response to changing of the configuration of the contour line. These devices are operatively associated with one another and operations of each of them are controlled by a control system.