A method for producing a weather strip of which the sectional shape is continuously changed in its longitudinal direction, has the steps of simultaneously extruding two rubber members out of two outlet ports formed in an extrusion head of an extruder so as to be close to and parallel with each other, each of the two rubber members having a uniform sectional shape in each longitudinal direction, corresponding to each of two pieces obtained by cutting the weather strip in its longitudinal direction, overlapping opposed side portions of the two extruded rubber members, joining the overlapped portion to obtain a joined weather strip of which the sectional shape is continuously changed in its longitudinal direction, and feeding the joined weather strip into a vulcanizing bath to be vulcanized. The overlapping step and the joining step are performed by feeding the two extruded rubber members between a receiving roller disposed in front of the extruding outlets, and a pressing roller disposed directly above the receiving roller. The receiving roller has a guide groove in its outer periphery, of which the width is changed in the peripheral direction of the roller, and the pressing roller presses the overlapped portion of the two extruded rubber members within the guide groove of the receiving roller.