The present invention pertains to a toothed belt comprising a back portion in which a core wire extending in the belt circumferential direction is embedded, and a plurality of tooth portions formed on the inner circumferential surface of the back portion at intervals in the belt circumferential direction, and including a back rubber layer formed on the outer circumferential side of the belt relative to the core wire, and a first rubber layer and a second rubber layer that are formed on the inner circumferential side of the belt relative to the core wire. The back portion includes the back rubber layer. The elastic modulus of the first rubber layer is larger than the elastic modulus of the second rubber layer. The first rubber layer is formed from a first cross-linked rubber composition including a first rubber component and first short fibers, the proportion of the first short fibers is 5-60 parts by mass with respect to 100 parts by mass of the first rubber component. The first short fibers are aligned in the belt longitudinal direction along the contour of the tooth portions, and the tooth portions include the first rubber layer and the second rubber layer which is interposed between the first rubber layer and the core wire.