Configuring the inside of a tooth portion 15 of a toothed belt 10 with a core rubber layer 14 and the outer periphery of the tooth portion 15 with a tooth rubber layer 12. Also, including short fibers in the core rubber layer 14. The tooth rubber layer 12 is formed by curing a rubber composition containing 10 parts by weight or less high-density polyethylene with 100 parts by weight of matrix rubber. The value of tan ´ for the tooth rubber layer 12 at 100-120°C is maintained at 0.100-0.120.
