PURPOSE: To easily measure the transmitted wave aberration of the toric lens by arranging such a plane mirror and a convex mirror that a high-precision surface can be manufactured on the focal line of the lens to be inspected.

CONSTITUTION: When the plane mirror 12 with high surface accuracy is arranged on the focal line of a cylindrical lens 6, light incident on the plane mirror 12 in the axis meridian section 6-1 of the lens 6 is reflected in a direction symmetrical with the normal to the reflecting surface and then travels back through the same path and reaches an observation part 11 through a half-mirror 3. Light in the power meridian section 6-2, on the other hand, is reflected by the plane mirrror 12 and the reflected light travels back through the same path while the reflection direction coincides with the incidence direction to reach the observation part 11. Consequently, the reflected light beams in the power meridian and axis meridian which reach the observation part 11 contain all information on the transmitted wave aberration of the lens 6 and interference fringes between the reflected light and reflected light from a reference plane 5-a form an interference pattern of the transmitted wave aberration of the lens 6 itself and the lens 6 to be inspected is not moved during the measurement, so the interference pattern has smooth continuation.