To improve a service life by getting rid of any possible scattering of rubber dust from a tooth part surface, reducing the extent of noises in time of running, and restraining any thrust force from occurring.

This is a helical toothed belt 1, which sets up plural pieces of tooth parts set up in the longitudinal direction, and embeds a core wire 3 in a back part 4, while it has covered a tooth fabric 5 on the surface of these tooth parts 2. The tooth fabric 5 of this belt is treated with a resorcinol- formalin-latex solution alone, and thereby rubber of the tooth parts 2 is made so as not to be exposed from an opening part of the tooth fabric 5.