PURPOSE: To perform experiment while a tester confirms the gaze of an observer, by providing an infrared irradiation part and an infrared receiving part at a position, which is in the vicinity of the ocular part of visual environment evaluation experiment but deviate from the visual field of the observer while providing a display apparatus at a position capable of being confirmed by the tester.

CONSTITUTION: Infrared rays from the infrared irradiation part 1 arranged at a position deviated from the visual field of an observer are allowed to irradiate the crystalline lens of the eye of the observer and reflected infrared rays from the crystalline lens are received by and infrared receiving part. When the visual field of the observer moves during evaluation experiment, the crystalline lens of the eye of the observer moves positionally and, therefore, infrared rays from the infrared irradiation part are reflected from a vitreous body 3. Reflected rays are received by an infrared receiving part 4 but light receiving quantity is far much as compared with a case reflected from the crystalline lens 2. When the quantity of infrared rays received by the infrared receiving part 4 is much, a display lamp 5 lights and a tester knows the movement of the visual field of the observer.