Objective material.
® An objective observation optical material comprises a sheet material composed of a plurality of spot-like transparent portions on an otherwise opaque sheet and each of the spot-like transparent portions is formed into a circular shape having preferably a diameter of 0.7 to 2.0 mm or substantially a polygonal shape (including one whose sides are curved arcuately) inscribing or circumscribing such a circle. The spot-like transparent portions are distributed in uniformly arranged positions so as to form connected regular triangles or squares whose sides are for example in the range from 2.0 to 5.5 mm.