PURPOSE: To eliminate the personal error of measurement and to increase the reliability of unit, by displaying the focus of lens and column axis through automatic measurement.

CONSTITUTION: The parallel light from the lens 1 is incident to the lens 2, and the image 5 of the chart 4 having required pattern is formed on the focus f2, and the image 5 is made to the image 7 through the iris 6 and the lens 3. The image 7 is scanned with the detection element 31, the signal obtained is wave shaped 32, and it is fed to the microcomputer 35 together with the output of the x, y axis pulse generation circuit 34 and the reference clock generation circuit 33, and the result of calculation is displayed 37 through the calculation of the spherical degree, astigmatism degree and column axis.