PURPOSE: To confirm the type of a lens rapidly and easily, by measuring a peak refractive force of a lens to be inspected for two different media and using the quotient of the measurement values as a material characteristic value.

CONSTITUTION: A first support arm 4 is fixed to a lower edge 3 of a guide rod 2, a second support arm 5 is mounted to the guide rod 2 via a guide sleeve 6, and a tensile force is given by a coil spring 7 for shifting in the direction of an arrow 8. Each single transparent plates 9 and 10 with a parallel plane are provided at the front edge of the arms 4 and 5, silicon elastic rubber cushions 11 and 12 are arranged on the opposite surfaces and are retained by frames 13 and 14, and a glass lens 15 is pinched between the cushions 11 and 12. The peak refractive force of a lens to be inspected for air is measured by a conventional method using a lens meter and then the peak refractive force for a second medium is measured by the device to calculate the quotient of the measurement value. Then, the quotient is not related to the radius of curvature of the lens and can be used as a material characteristic value.