To firmly install a retroreflective lens in a base part of a delineator pole by an assembling method.

This delineator pole is composed of a sign pole body of forming a core pedestal on the lower end, a base for surrounding the core pedestal by fitting to the outer periphery of the core pedestal of the sign pole body, and the retroreflective lens of integrally joining an exposure part and a base part having a reflecting surface having a diameter larger than this part via a stepped part. A fitting surface of the core pedestal and the base is formed into a tapered surface of diametrally contracting upward. The exposure part of the retroreflective lens is inserted from the inside into a through-hole arranged in the base, and the tip is exposed outside the base. The sign pole body with the core pedestal is inserted into the base from below in this state, and the lens is installed on the base by sandwiching a base part of the lens between an outside surface of the core pedestal and an inner surface of the base.