A lens arrangement for telescopic illuminator includes a reflector. The reflector has a cavity defined therein. An inner periphery of the cavity is annularly formed with a conical surface. The conical surface is inwardly inclined. A convex lens is disposed in the cavity and positioned in a middle part of the reflector. A tapered portion is annularly disposed on an outer periphery of the reflector and inclined toward the inner end of the reflector. A flat surface is formed on the inner end of the reflector. The flat surface has a receiving hole centrally defined therein and passing therethrough. A lamp movably is disposed adjacent to the reflector. The lamp is born by an aluminum board.