When a molded portion of a weather strip is molded, a slit, from which a core body is taken out, is formed in a mounting base portion thereof. Also, plural blocking clips are provided at predetermined intervals along the slit. The blocking clips comprises a base portion, which constitutes a part of the mounting base portion, a fitting portion fitted into the slit, a lock portion locked on an inner surface of the mounting base portion, and an engaging projection formed in such a way as to project from the base portion. A fitting groove, into which the engaging projection is fitted, is formed in the mounting base portion. After a core body is taken out of a molded portion precursor, the blocking clip is attached thereto, so that the molded portion is obtained.