Toothed belt and toothed belt transmission device

A toothed belt comprising:

• a back portion;
• a tension member embedded in the back portion in a belt longitudinal direction and comprising a twisted cord comprising a steel fiber;
• a plurality of belt teeth formed on an inner peripheral side of the back portion along the belt longitudinal direction;
• and
• a cover layer provided between the tension member and a belt tooth bottom formed between the belt teeth, the cover layer being exposed as part of the belt tooth bottom,
• wherein the toothed belt has a total belt thickness of 9 mm to 16 mm, and the cover layer has a thickness in a range of 0.3 mm to 0.6 mm,
• the back portion including a part disposed on a side of the tension member opposite to the plurality of belt teeth, and
• the back portion, the belt teeth, and the cover layer are integrally formed of a thermoplastic elastomer.