To provide a method for producing a V-ribbed belt which can be molded by only one process without polishing a rib thereof, and the tension of which is hardly lowered.

The V-ribbed belt 1 comprises: an extension 2; a compression portion 6 which has a plurality of ribs 7 extending in the peripheral direction of the belt; and a core wire 3 to be buried along the longitudinal direction of the belt between the extension 2 and the compression portion 6. The method for manufacturing the V-ribbed belt 1 comprises steps of: using a belt vulcanizer comprising an outer die on the inner peripheral surface of which a rib model is carved, and an inner die on the outer peripheral surface of which a flexible jacket is mounted; winding the extension 2, the polyester core wire 3 which has 2-4% elongation when 100N is applied thereto, 5-10% elongation when 200N is applied thereto and 5-15N contraction stress, and the compression portion 6 successively around the surface of the flexible jacket; expanding the flexible jacket to extend the extension 2, the polyester core wire 3 and the compression portion 6 all at once; performing vulcanization while sticking the compression portion 6 to the rib model of the outer die; and cutting the demolded vulcanization belt sleeve into pieces having predetermined widths.