The bromoethynylanthracene monomer with 3,5-di-tert-butyl-4-acetoxyphenyl group was newly synthesized and was polymerized by Pd(O) catalyst to give the head-to-tail regulated polymer with DP = 12. The ESR spectra of the anthracene-based polyradical suggested an effectively delocalized spin distribution on the backbone anthracene. The Deltam(s) = +/-2 forbidden transition ascribed to the triplet species was observed at g = 4 in frozen toluene glass. Magnetization and static magnetic susceptibility of the polyradical were measured using a SQUID magnetometer. The average spin quantum number was beyond S = 1/2, indicating the ferromagnetic interaction.